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T2-7.4

Quick Overview

Advanced 7.4 system. Four THX Select certified 10in subwoofers and THX Ultra2 certified fronts

Create the ultimate audio system for small to medium sized rooms
  • 7.4 Speaker System for the absolute Home Theater experience
  • THX Ultra2 certified floorstanders
  • THX Select certified Center, Dipole Surrounds and Subwoofers
  • Four 10-inch, 120W subwoofers for room shacking bass and effective standing wave control
  • Deluxe gloss finish, with wooden sides in black ash
$4,699

    Associated Products

  • T2-7.4
    THX-10SUBT-BL

    Powerful 10in THX Select Certified active subwoofer

    $499
  • T2-7.4
    THX-D-BLA

    Award Winning Surround Effects Dipole Speakers with THX Select Certification

    $599
  • T2-7.4
    THX-CT-BLA

    Award Winning Dialogue Center Speaker with THX Select Certification

    $349
  • T2-7.4
    TX-T2SE-BL

    Awarded 2-way Special Edition pair with THX Ultra2 certification

    $999
  • Electronic Tweeter Protection

    Listen safely, even at high levels

    The embedded protection circuitry interrupts the tweeter’s operation at excessively high levels, preventing any possible damage. The added benefit of this feature is that it actually warns you of potential woofer damage as well, let alone your amplifier!

  • +/-1.5dB Accuracy of Frequency Response

    Enjoy accurate, studio quality audio

    Smooth, balanced and truly realistic sound that faithfully represents the musical instruments, the human voice and all kinds of modern movie effects.

  • Top-mounted Rotating Tweeter

    Enjoy top-notch high frequencies with wide dispersion

    Free of diffractions caused by the speaker’s enclosure, the tweeter offers airy, transparent sound, with wide dispersion. The rotation feature allows you to direct all high frequencies towards you, even if the speaker is pointing straight ahead!

  • Double Chamber Enclosure

    Enjoy powerful bass performance from relatively small-footprint speakers

    Each woofer works in a carefully engineered frequency region, determined by the volume of the chamber, the diameter of the port and the crossover. This results in a stunning, tightly controlled bass, beyond what the speaker’s dimensions might imply.

  • Controlled Sonic Dispersion

    Listen to what you must, without unwanted sonic elements

    The meticulously engineered horizontal and vertical sound dispersion pattern of the TX-T2SE, achieves a dramatic reduction of the unwanted floor and ceiling reflections which cause unwanted sonic colorations. Thus, direct and reflected sound, has the same character.

  • 7'' Woofer

    Enjoy clear and detailed low and mid frequencies

    Thanks to a special “sandwich” of rigid and low mass materials, Crystal Acoustics’ woofers are characterized for their extremely linear behavior and ultra fast response.

  • Silk Dome Tweeter with protective diffuser

    Enjoy smooth, undistorted audio with detailed, airy highs, no matter where you stand in the room

    These highly sensitive silk dome tweeters offer exceptionally transparent and detailed highs, even with low -powered amplifiers. The added diffuser protects the tweeter and offers pleasant dispersion for many listeners in the room.

  • Two Silk Dome Tweeters

    Enjoy evenly dispersed surround sound and high-power output

    These highly sensitive silk dome tweeters offer exceptionally transparent and detailed highs, even with low -powered amplifiers. The electronic protection circuitry ensures trouble-free listening at high volume.

  • 7" Woven Microfiber Woofer

    Enjoy clear and detailed low and mid frequencies

  • Conical Steel Phase Plug

    The brushed steel phase plug at the center of the woofers was carefully engineered to ensure the wide dispersion of all mid frequencies for an enjoyable listening experience in more than one listening position.

  • Glossy Black finish

    Integrate the speakers with your internal decor

    Demonstrate your speakers, instead of hiding them out of sight! Ugly, old-styled speakers are a thing of the past. Luxurious glossy black is today’s motto for every living space connoisseur.

  • Powerful Woofer Magnet

    Enjoy plentiful LFE impact and ultra-fast response

    The premium materials into the core of each woofer driver, ensure an outstanding performance with any kind of listening material.

  • High Power Capability

    Listen for long periods of time, with no fatigue

    Enjoy your music and movies at realistic listening levels without feeling fatigued or sonically “over-saturated”.

  • Narrow Front Baffle

    Enjoy a clear, precise and focused stereo imaging

    The ultra narrow front baffle of the speakers is actually no larger than the diameter of the speaker’s woofers. As a result, it’s impact on sonic performance is minimal, allowing you to enjoy a tightly focused stereo image.

  • Magnetic Shielding

    Avoid damaging magnetically sensitive devices and media

    Each loudspeaker is magnetically shielded so as to prevent any possible damaged when placed near CRT TVs or storage media that is sensitive to magnetic fields, such as hard disc drives.

  • THX Ultra2 Certified

    Experience every movie or concert, exactly as the artists intended

    Optimized electronics and carefully engineered dispersion result in a stunning, powerful and dynamic surround sound. Experience nuanced, lifelike multichannel audio for movies, music and video games!

  • Down-firing design

    Enjoy powerful low frequencies with less localization

    Even at higher crossover settings (over 80Hz) the subwoofer can remain relatively “hidden”, being more difficult to localize than its more traditional, front firing “brothers”. Furthermore, it allows for a more uniform LFE dispersion.

  • 120W Amplifier

    Fill every room with bombastic low frequencies

    The high quality electronics that compose the 120W amplifier, ensure plentiful impact with control as well as immediate, fast transients with every sonic material.

  • Bass Reflex Port

    Feel the powerful impact of every explosion

    The large front-firing ports deliver powerful bass output with extended response

  • Four THX certified subwoofers

    Create the ultimate home theater experience, according to THX specifications

    Using four Crystal Acoustics THX certified subwoofers, you can achieve the maximum SPL, for the ultimate low frequency experience.

  • Black Ash side pieces

    Enhance your home design with beautifully crafted loudspeakers

    Wood is beautiful to look at, even when it comes as a feature of high-tech devices. Naturally “related” to optimal sound reproduction, it was the best possible material on which to form the good looking curves on the sides of the flagship TX-T2SE.

  • 10'' Woofer

    Enjoy deep, extended bass response

    The light but rigid, specially treated paper cone couples with the carefully engineered electronics to offer deep bass with extended dynamics.

  • THX Select Certified

    Experience every movie or concert, exactly as the artists intended

    As with the Ultra2 standard, THX Select certified speakers offer studio, powerful and dynamic surround sound, optimized for small to medium-sized rooms.

    • LoudSpeakers

    • Want to get into the basic concepts of Sound, Hi-Fi and Home Theater?

      • What is sound and what are its basic characteristics?

        Sound propagates through the air in the form of an acoustic wave.

        Sound is a form of energy. It is generated by an audio source and is detected by human hearing. A loudspeaker converts the electric energy from the amplifier into acoustic energy we hear by moving air. Sound propagates through the air in the form of an acoustic wave. This acoustic wave carries the audio information of the initial disturbance of the air caused by the loudspeaker, according to the rules of wave propagation.

        A wave is a disturbance or variation that transfers energy progressively from one point to another. It may take the form of an elastic deformation or of a variation of pressure. According to the rules of physics, a wave is described by its wavelength, its period, its frequency and its speed.

        Wavelength is the distance the audio wave travels until it completes a full cycle and it starts repeating itself. In physics the wavelength is symbolized by the Greek letter λ and is measured in metres.

        Period is the time required by the audio wave to complete a full cycle, or to cover a distance equal to its wavelength. It is symbolized by the letter T and is measured in seconds (sec) or milliseconds (msec).

        The frequency of an audio wave indicates the number of cycles generated in one second, which is how many times the audio wave repeats itself in one second. It is symbolized by the letter f and is computed in Hertz (Hz) or kilohertz (kHz). One Hz means one cycle per second. One kHz is one thousand cycles per second. Humans can hear sounds with a frequency between 20Hz and 20,000Hz (20kHz). Age and long-term exposure to loud environments reduce this range.

        The speed of a wave indicates how fast it travels through the medium it propagates. The speed of sound is measured in metres per second (m/sec) and is symbolized by the letter c. The speed of sound through air is influenced by the temperature of the air, which affects air density. At 21 degrees centigrade the speed of sound in air is equal to 344 m/sec.

      • What is the purpose of each speaker in a home cinema system?

        The purpose varies according to the speaker placement and characteristics.

        The front speakers (left/right) reproduce the main musical soundtrack, off-screen dialogue, and transition sound effects.

        The centre speaker reproduces on-screen dialogue, the central images of the musical soundtrack, and transition sound effects.

        The surround speakers provide sound effects and ambience, while the subwoofers provide dynamic low frequency information.

      • How many types of speakers are there based on their placement type?

        There are 3 types of speakers based on their placement type: Floorstanding, Bookshelf, Wall Mounted

        Τhere are three types:

        [image]

         

        Floorstanding

        [image]

         

        Bookshelf / Stand mounted

        [image]

         

        Wall mounted

        You can choose any type for hi-fi or home cinema use.

      • Should I listen to my speakers with or without grille?

        Normally speakers are designed so that their performance is best with their grilles in place.

        [image]

        Normally speaker manufacturers design their speakers so that their performance is often best with the grilles in place. Removing them could cause an over-brightening of the sound (richer treble content) which, although initially impressive at first audition, doesn't necesserily translate to more accurate reproduction.

        Crystal Audio speakers on the other hand are designed using minimalist frame grilles that are 'sonically transparent' eliminating unwanted sound absorption and diffraction. You can enjoy the full sonic experience of the Crystal Audio speakers with or without their grille. It all goes down to taste.

        Of course, if you have children or pets we would strongly suggest keeping them on, or you risk damaging the speaker.

      • If I already have a quality stereo system, do I still have to buy a complete new home cinema system?

        You should at least have a set of acoustically matched fronts and center.

        Not necessarily. Ideally you should have at least all three main speakers (front and centre) acoustically matched. If your stereo speakers are quality performers, however, you just have to ensure that the centre speaker you buy also performs up to their standards.

        Using the calibration features of modern day home cinema receivers you can alter some of the sonic characteristics of the main speakers so that they more closely match.

      • Why do I need a subwoofer?

        To realistically reproduce low frequencies and feel what the director or musician intended.

        Bass reproduction places great strain on speakers. Speaker manufacturers therefore resorted to producing an independent unit called a subwoofer. Its task is to exclusively reproduce the lowest octave of the audible frequencies (20Hz to 80Hz according to the THX specifications, or up to 120Hz maximum for smaller main speakers). Thus the main speakers are released from the work of recreating low frequencies. As a result they behave more linearly, are more efficient, while at the same time are much smaller in size and of course less expensive. Since low frequencies are largely non-directional, the subwoofer reproducing them can be placed far from the main speakers and still sound as if they were emanating from them.

        [image]

        Furthermore, if you have all the low frequencies coming from one speaker (the subwoofer) it can be placed in the most suitable part of the room to minimizes standing waves, thus giving a more uniform bass reproduction. Get more information on standing modes.

      • What are the benefits to using an active subwoofer?

        It will enhance all low frequency output, plus it will allow your amplifier to perform at its best.

        There are many good reasons to add one and ideally two subwoofers to your system. The first reason is to add bass to a system whose main speakers lack good bass response

        Another reason is to remove the bass reproduction requirement from your other speakers, which improves their performance by minimizing inter-modulation - that is the non-linear mixing of sound with different frequencies.

        In addition if you use an active subwoofer, you will free up your amplifier’s power reserves, improving overall performance. Adding a subwoofer to your system must be done carefully. The subwoofer must be matched to the other speakers.

        You must select the correct cut-off point for the low frequencies produced by the subwoofer. You must match the level of the subwoofer to the other speakers, so that the bass is not over emphasized.

        Finally you must position your subwoofer in the correct place. It is true that our ears cannot easily tell where the bass comes from. As a result we can get by with using only one subwoofer for bass reproduction. However we must make sure that its position does not create standing waves.

        Using four subwoofers is preferable as you will get a better bass performance and will have less of a problem with standing waves, since the bass will originate from many locations in the room. The much more smooth bass performance across many different positions in your room will justify the extra cost of them.

      • How can my Home Theater elevate my gaming experience?

        Modern games have embraced surround sound, offering immersive, dynamic soundscapes.

        Let’s face it; we are not back in the 90's when gaming was just kids' entertainment, enjoyed through a PC with cheesy speakers, or the, small by that time, TV and its integrated speakers. Games are now designed using the most state of the art visual techniques and the most elaborate sound effects. A whole team of experts are working on the scenario, the direction, the lighting (just like a movie) and professional studios are used to produce and mix the sound effects. Games that are mostly enjoyed by the 29 years old fan (in average) and which absolutely require a modern, high performance multichannel Home Theater system to immerse the gamer into the realistic action it is designed to offer.

        Now that the connection with the Home Theater system is as easy as to say HDMI, your gaming experience can take a whole new dimension, heard and viewed through your quality system. Enjoy a bright and real-life size image together with thrilling bass frequencies from your subwoofer and immersing rear effects from your surrounds now!

      • How can I get the best out of an iPod/MP3 player using my hi-fi/home cinema speakers?

        Given the high quality of modern compression algorithms you can directly connect them to your system

        When compressed audio, mostly in the form of MP3 files, hit the market, it was initially questionable whether there was any point in using quality speakers to reproduce such compressed music content.

        Today sophisticated compression algorithms, along with the 'luxury' of working with higher bit rates thanks to cheaper disk space and faster network connections, MP3 songs can deliver extraordinary quality.

        Now you have your iPod and MP3 player stuffed with hundreds or even thousands of your beloved songs, arranged in playlists or by genre or by artist. Why not hook it up to your hi-fi/home cinema system and enjoy all your music at top-notch quality?

        Just use a mini jack to RCA cable, connect this from the iPod/MP3 player to the ‘analogue audio in’ of your amplifier and turn your player into a powerful and flexible music system.

         

      • What is a speaker's task and what determines its performance?

        It is to reproduce realistically every sound from a sound source

        Of all the components of an entertainment system, none has a task as difficult as a loudspeaker. This box is called upon to reproduce the sound of everything from a human voice, to drums, to a cello, and much more. It must do this in a realistic way that convinces us that what we are hearing is live.

        There are many desired aspects of a loudspeaker’s performance, including:

        - Flat and wide frequency response
        - Low distortion over a wide range of levels
        - Good transient response
        - Appropriate dispersion
        - High sensitivity
        - Low impedance

        The first ingredient that determines a loudspeaker’s performance are the drivers (speakers) themselves. They convert electricity to sound, by driving the air in front of them. Their construction (intensity of magnet, size and type of diaphragm, voice coil used, overall geometry) is crucial, in conjuction with the enclosure employed, to the speaker’s the performance.

        Most speakers’ enclosures are boxes or cabinets of various designs. The quality and type of enclosure (open box or closed box) is a basic ingredient of the speaker’s performance as well.

        The drivers are fed signals that are filtered from the crossover of the loudspeaker so that music is split into smaller ranges of frequencies, for specialized drivers (woofers and tweeters) that cover these ranges. Crossover network quality is therefore a basic ingredient of the speaker performance.

        Finally, and most importantly, the room where the speaker performs is a crucial ingredient of the performance. Speakers will sound drastically different in different rooms.

      • From hi-fi to 5.1 and 7.1 configurations. What to choose?

        Ιf you can afford it go for a 7.1 system and get the full experience of modern recordings and movies

        5.1 channel home cinema receivers have been the standard for over a decade. They provide an impressive surround sound experience, especially in small to average-sized rooms. A 5.1 channel system comprises:

        1. A centre channel to carry a significant portion of the soundtrack and most of the dialogue, keeping the voices centered when they need to be
        2. Left and right front channels to create the soundstage for the movie soundtrack, reproducing much of the music and special effects, and helping the sound follow the action that is moving across the screen
        3. Left and right surround sound channels to create a lifelike sense of spaciousness, providing the ambient sounds for a movie or audience reactions in a concert video
        4. The subwoofer, which provides the low frequency effects (sometimes referred to as an LFE), giving weight and impact to movie soundtracks, particularly in action features

        A 7.1 channel system incorporates all of the above elements, but adds an extra two surround effects channels. Side sound effects and ambience are directed to left and right surround channels, and the rear sound effects and ambience are directed to two rear or back channels. In this set-up the surround speakers are set to the side of the listening postion and the rear or back channels are placed behind the listener. Here the additional channels (sixth and seventh) provide a more intense surround experience by enabling enhanced localization of sound effects.

        [image]

        There are an increasing amount of Blu-ray soundtracks that contain 7.1 channel information - whether it be 7.1 channel uncompressed PCM, Dolby TrueHD, or DTS-HD Master Audio. If you have a 7.1 channel receiver with audio input and processing capability via HDMI connections (not pass-through only connections), you can take advantage of some, or all, of these audio capabilities.

        Also, even with playback of standard DVDs, if your DVD soundtrack only contains Dolby Digital or DTS 5.1 or, in some cases, DTS-ES 6.1 or Dolby Surround EX 6.1 soundtracks, by using the Dolby Pro Logic IIx extension or other available 7.1 DSP surround modes that may be available on your receiver, you can still extract a 7.1 channel surround field from both two or 5.1 channel source material.

        To cut a long story short, if you can afford it go for a 7.1 system and get the full experience of modern recordings and movies!

      • What are the Dipolar and Bipolar speakers? When are they used?

        Dipolar and Bipolar speakers are used as surround speakers in a Home Theater system.

        [image]

        Both Dipolar and Bipolar speakers are used as surround speakers in a Home Theater system. They have two or more speakers that output sound from opposing sides of the cabinet, that is towards the front and the rear of the listening room if they are used as side surrounds in which case they are mounted on the side walls. While the Bipolar speakers however have the speakers on the opposing cabinet sides emitting sound in-phase (speaker diaphragms move in and out simultaneously), the Dipolar speakers emit sound out-of-phase (when one speaker's diaphragm moves out, the other is moving in and vice-versa).

         

        This results in the Dipolar speakers producing a more diffuse sound field, with little direct sound reaching the listener, but instead with relfections that encircle him. However the null that is produced towards the direction of the listener (because of the cancelation of out-of-phase waves) results in a loss of acoustic energy and a strong colouration of the reproduced sound. The ambience may be created but more direct auditory cues cannot be faithfully reproduced. For this reason Crystal Audio has designed a Surround speaker (THX-D) that preserves all the advantages of monopoles (direct firing speakers) and bipoles/dipoles while at the same time being elegant and friendly for wall mounting installation.

         

        The THX-D speakers use a 6.5'' woofer pointing to the user that provides all the information up to the mid-highs, thus giving all the basic sonic cues. The mid-highs to high frequencies are reproduced by a pair of tweeters mounted on angled sides of the cabinet facing towards the front and rear walls of the listening room and connected in phase. Thus they reach the listeners via reflections from the wall, giving a unique spaciousness and envelopping feeling. The highs are not coloured by the destructive interference of the out-of-phase waves but instead reach the listener without any spectral distortion. Furthermore, both the power (averaged) and on-axis response are smooth for the best surround reproduction anywhere in the room.

    • Can you explain what do all those speaker specifications really mean?

      • What is the nominal input power?

        The continuous power (RMS Watts) that a speaker can handle, without being damaged.

        The nominal input power of a loudspeaker is the continuous power (Watt RMS) that can be absorbed by the speaker without it being damaged, and not a measurement of minimum amplifier power needed to drive it. Naturally the speakers can handle much higher power peaks for small periods of time (a few 1/100s of a second). If a speaker combines high nominal input power with a high sensitivity, then we can generate music and sound at realistic levels without compression or distortion.

      • Is the nominal input power of a speaker a measure of quality audio reproduction?

        No, input power does not relate to performance in any way

        No! The input power of a speaker by no means affects its performance. A high quality speaker in general must provide a smooth frequency response both on-axis (in front of the tweeter) and off-axis (at an angle from the tweeter axis), which is done through controlled dispersion, so that it doesn't induce any unwanted colorations in the sound. Furthermore, it must keep distortion at very low levels and at the same time be sensitive enough, without a very low impedance, so that almost all amplifiers can drive it successfully. Although it is a great asset to have high power speakers that can handle that extra boost we need to rock everyone from their seat during a party or movie viewing, the nominal input power is not at all related to the frequency response, dispersion and sensitivity of the speaker.

      • What is the so called “break-in” period and what should I consider?

        It is a continuous playback period, after which, the speakers gain full performance capability.

        Every audio component in the world of Hi-Fi and Home Theater is usually accompanied with what is called a “break-in” period. This is usually a period of some days that the audio component is required to operate, before it can perform at its best. Like for ex. in power amplifiers or receivers where the power supply and capacitors “open up” after some hours of operation, the same goes for loudspeakers, where their woofer suspensions become “softer” and more accurate. After the break-in period is complete, the loudspeaker can perform as the manufacturer intended and is ready for critical listening sessions.

        Crystal Acoustics loudspeakers will usually require about 100 hours in moderate playback levels before they can perform at their best, although the break-in period continues even after this time frame. It should also be considered that the absolute time of an actual break-in is affected by the speaker type, the amplifier that drives it. the playback level as well as whether the break-in period is performed through continuous or interrupted playback periods.

        Tip: In order to perform a quick and effective break-in of your loudspeakers, you can follow this tip.

        1. Place your loudspeakers face-to-face, in close distance.
        2. Wire the first loudspeaker as indicated and reverse the +/- wiring of the second loudspeaker, thus reversing its phase.
        3. Initialize the playback procedure, choosing some rich sounding, full band tracks that equally extend to all frequencies. Because of the out-of-phase setup of the loudspeakers, you will notice that the audio output of the loudspeakers is actually canceled by a great amount. As a result, you can leave your loudspeakers breaking-in without annoying your neighbors, even when you are away from home.

      • What do all these speakers specifications mean?

        Specifications can be confusing and some are more important than others.

        Sensitivity: Sensitivity is a measure of how loudly a speaker will play 2.83 volts, one metre in front of it. Since loudness is measured in decibels of Sound Pressure Level (dB SPL), the sensitivity rating is specified in dB SPL/2.83V/m. Note that 2.83 volts corresponds to one watt when applied to an 8 ohm speaker (P=V2/R, hence 1W=2.832/8). Since modern amplifiers are constant voltage sources across most of their working range, specifying the sensitivity at a specific voltage rather than the older standard of 1W (which translates as a different voltage for speakers that aren’t 8 ohm designs) provides for a much more consistent way of appreciating the sensitivity of speakers.

        The sensitivity of a loudspeaker is a very important specification: the greater the sensitivity, the louder the speaker plays, and/or the smaller the amplifier it requires. As a rule, high sensitivity speakers decrease the cost of the required amplifier, offer lower distortion and a greater dynamic range.

        Nominal Input Power: The nominal input power of a loudspeaker is the continuous power (Watt RMS) that can be absorbed by the speaker without it being damaged, and not a measurement of minimum amplifier power needed to drive it. Naturally the speakers can handle much higher power peaks for small periods of time (a few 1/100s of a second). If a speaker combines high nominal input power with a high sensitivity, then we can generate music and sound at realistic levels without compression or distortion.

        Impedance: The impedance of a loudspeaker is a measure of how difficult a load it is on the amplifier it is connected to. The impedance of a loudspeaker varies significantly depending on the frequency. Most loudspeaker specification sheets provide the nominal impedance, which more-or-less is the average over the full frequency range. Because the impedance is an average, two speakers with the same nominal impedance may have vastly difference actual impedance at given frequencies. Keep in mind that a typical 8 ohm loudspeaker may vary from a minimum of 5 ohm to over 30 Ohm depending on the frequency. A lower loudspeaker impedance causes an amplifier to output more power and to reproduce higher volume levels and places a greater task on it.

        Dispersion: How widely and evenly a speaker spreads its sound. A speaker with narrow dispersion beams its sound forward like the beam from a flashlight. A wide-dispersion speaker evenly covers the entire listening area with sound. Speakers must have a wide horizontal dispersion for two reasons. Reflections from sidewalls must have as close frequency content as the on axis radiated so that unwanted colorations are minimized. Secondly, wide horizontal dispersion permits all listeners to enjoy music and movies wherever they sit in the room.

        Crossover Frequency: The crossover frequency is the frequency at which the signal is split to the different drivers of a multi-way speaker system. In a typical two-way system, the crossover frequency between the woofer and the tweeter will be set around 2500Hz.

        Cutoff frequency: The frequency at which the signal falls off by 3dB (the half power point) from its maximum value. Also referred to as the -3dB points, or the corner frequency. The lower it is, the more bass the speaker can reproduce.

      • Why do different speakers have different impedance (ohm) ratings?

        Different speakers have different components which create variations in their total summed impedance

        An ohm is a measure of resistance (impedance) to the flow of electric current through a device. The impedance rating of a particular speaker varies depending on the frequency of the signal. Different speaker models have different impedance ratings. The nominal impedance that is usually specified for a speaker is an average rating of the impedance over the whole frequency band. Higher impedance speakers are an easier load on the amplifier since there is less current flowing into the speakers.

        Therefore the amplifier’s operating temperature is cooler, since it is delivering less power. If a particular amp is designed correctly, as far as heat dissipation is concerned, then a lower impedance speaker can be used to get the most power out of it. Many stereo amps and receivers give a power rating for both 4 and 8 ohm speakers.

        Some high-end amplifiers can drive speakers with one ohm impedance! On the other hand, many multi-channel receivers are designed to handle only 8 ohm speakers, since the heat generated by their multiple amplifiers is excessive. It is advised to choose an amplifier that can drive at least 6 ohm speakers. Therefore, you can connect the main speakers with an impedance down to 4 ohm provided that the surrounds are 8 ohm designs.

      • What does the sensitivity rating actually mean?

        It means how loud a speaker can play, when fed with a signal of given power.

        The sensitivity rating of a speaker is very valuable because indicates how efficient a speaker is. In other words, it tells us how loud the speaker will play when it is fed with a standardized signal.

        Years ago, loudspeaker sensitivity was rated as the sound level at a distance of one metre for an input of one watt. Power input is voltage2/resistance. Because loudspeakers do not have the same impedance at all frequencies, a sensitivity rating would apply only at a single frequency (or in a confined frequency range at best). Obviously, rating sensitivity according to power input does not work well. The domination of solid-state amplifiers really provided the solution. These amplifiers are essentially constant-voltage sources, with power rated according to what they can deliver into an 8 ohm resistor. If the load impedance drops to 4 ohm, the power will double; at 2 ohm the power quadruples and so on, until the amplifier cannot deliver any more current or dissipate any more heat. This permits us to define an input voltage, not an input power, to rate the sensitivity.

        The sensitivity rating is nowadays given (or should be given!) in number of dB SPL /2.83V /1 meter. For example, a particular speaker may have a sensitivity rating of 92dB SPL/2.83V/metre. This means that when a signal of 2.83V in amplitude is driven to the speaker, the generated sound is 92 decibels when measured at 1 metre from the speaker.

      • How do you calculate the Sound Pressure Level in your Room?

        There are three rules you must follow. Learn more in the full answer of this question,

        Sound Pressure Level: The three rules to calculation
        The following rules are used to calculate the Sound pressure Level (SPL) in the room depending:

        - On the distance of speakers and listener:
        - Doubling the distance results in a 6dB reduction of the sound level
        - At half the distance the sound level is increased by 6dB The sensitivity of our speakers:
        - Two speakers deliver 3dB more than one speaker (stereo configuration)
        - The power of our amplifier:
        - Twice the power (watt) results in a 3dB increase of the SPL (under the assumption that the speakers can handle the extra power without distortion or damage) 

        Sensitivity: The sensitivity of a speaker determines the generated Sound Pressure Level. The sensitivity is measured in dB SPL/2.83V/m, depending on the sound pressure level in dB that is generated at a distance of one metre and an input signal of 2.83V (which corresponds to one watt of power when applied to an 8 ohm speaker) from the amplifier. The greater the sensitivity:

        - The louder it plays
        - The smaller the power amplifier it requires

        High sensitivity speakers decrease the cost of the required amplifier and offer low distortion and greater dynamic range.

        But what is the real gain of 3dB? A speaker with 3dB higher sensitivity requires half the amplifier power to produce the same sound level. For example, a speaker with 94dB sensitivity requires half the wattage of a speaker rated at 91dB sensitivity to produce the same sound level. Thus, if the first speaker requires 100 watts to produce a certain sound level, a 91dB speaker will need 200 watts and a 88dB speaker 400 watts!

        - How much more money do you need in order to buy a 400 watt amplifier and a speaker that can handle 400 watts?

        In addition, the distortion of a speaker with a 400 watt input is greater than a 94dB sensitivity speaker with only a 100 watt input

      • What do speaker measurements reveal and how are useful?

        Read below to have a better understanding of speaker measurements.

        Since the very first days of speaker design and evaluation there has been a big debate on what measurements tell us about the speaker: how they correlate with our listening experience; to what extent the designer can rely on them; and how accurate and repeatable they are. Of course, these are questions that are the subject of specific fields of acoustics, such as psychoacoustics, and it would be impossible to cover everything here. However, we can give some useful insights to the user that wants to know more about the scientific aspect of acoustics as opposed to the hocus pocus that often surrounds speakers!

        The main measurement a designer cares for is the frequency response of the speaker as measured at a specific distance (one or two metres from the speaker) from the driver and exactly on the axis of it (on-axis). This shows the response of the speaker for all frequencies of the audible band. Whatever you may hear and read about, 'flat' is unquestionably the best response. It is the only reference one can rely on, and it is what designers should thrive for. A flat response means that the speaker reproduces all sounds without emphasizing or reducing specific frequencies that would result in a sonic coloration.

        Now watch out because there is a big problem here. Room acoustics truly define the lower frequency response of a speaker. In order to have accurate and repeatable measurement in many places for bass, we either must have a huge room, so that sound reflections don't influence the measurement, or we must employ a technique called Near-Field measurement. In this technique, the low frequency response of the speaker (and port(s) if any) is measured with the measurement microphone almost touching the cone, thus eliminating the contribution of all reflections whose magnitude is much smaller than the original signal. This measurement is then spliced with the on-axis measurement at a certain frequency, to give a very good approximation of the speaker’s response in an open space, with no physical boundaries nearby.

        The interesting point of the accurate near-field response is the frequency where the Sound Pressure Level of the speaker falls by 3dB compared to its average value. This is referred to as the f3 and is a measure of the ability of the speaker to reproduce low frequencies. Of course when evaluated in a realistic room the speaker's bass will be quite different due to the standing waves (room modes). However, the flatter the response up to the f3 frequency means the easier it will be to find an optimum place for it in the room that gives a smooth result.

        Then we have the frequency measurements performed at angles off-axis. These depict phenomena as the summation issues introduced by the phase shifts of crossover networks, etc. Again here we want to be as close to the on-axis response (which should be the flattest it gets!) as possible. In this way we are pretty sure that the reflected sound from the ceiling, floor and sidewalls will have the same sonic character as the direct signal. We need to confirm as well that the crossover network used does not cause a big response deviation off-axis.

        Another important measurement is the impedance versus frequency graph. This depicts the overall impedance of the speaker (including the resistance of the coil, its inductance along with the effect of the air and the enclosure interacting with the driver) from 20Hz to 20kHz and shows where the minimum impedance occurs and what is its value. Normally we want the minimum impedance to be higher than 3-4 ohm, so that pretty much any amplifier can drive the speaker. In high-end speakers however values of minimum impedance down to even one ohm are not unusual. The frequency at which the lowest impedance is observed is also important. If the frequency of lowest impedance is high, the load is easier on the amplifier, because in this area the power of audio information is small. If the lowest impedance frequency is in the mid or low range, then the speaker is considered a difficult load, since there is a great percentage of the audio power in this range.

    • Need a more detailed analysis on Speakers theory?

      • What are the different types of speaker design?

        There are two types, involving closed and open design principles.

        Based on the enclosure (cabinet) construction, speaker designs include the following:

         

        Acoustic suspension enclosures (closed-box) are air-tight, since they use the enclosed air to dampen the behavior of the woofer. When the woofer moves forward a vacuum is created behind the woofer that sucks the woofer back to its resting position. When the woofer moves backward there is an internal air pressure increase, which pushes the woofer to its resting place. A properly designed acoustic suspension loudspeaker has tight and deep bass with a gradual roll off below its cut-off frequency.

        However, acoustic suspension loudspeakers tend to be inefficient since the acoustic energy generated by the back of the woofer is not used. A ported enclosure is another way to use the energy that is wasted by an acoustic suspension loudspeaker. By opening an appropriately sized hole (bass reflex) in the enclosure and attaching a pipe of specific length to it, the low frequencies generated in the enclosure come out in phase with the bass generated by the front of the woofer. Varying the size of the hole and the length of the pipe varies the low frequency extension. Ported enclosures are much more efficient than closed-box designs, resulting in much smaller enclosures for the same cut-off frequency. As for the bass response below the cut-off frequency, this rolls off more steeply than in the closed-box configuration.

      • How do speakers work?

        By converting electric signals into sound.

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        A loudspeaker (or ‘speaker’) is an electro-acoustic device that converts electrical signals into sound. Speakers pulse in accordance with the variations of an electrical signal and sound waves propagate through air.

        We will give a brief description of how electrodynamic speakers (the most commonly used type of speaker) work to reproduce as faithfully as possible the various sounds that nature and musical instruments produce.

        Electrodynamic speakers are the most popular speakers. They come in various shapes, sizes and price brackets. Our familiar cones and domes characterize electrodynamic speakers. They are the diaphragms that generate the sound and usually the only visible parts of a loudspeaker. The electrodynamic speakers’ operation is based on the principles of electromagnetic induction. That is, when a conductor moves in a magnetic field it experiences forces that result in the generation of an internal electric field and potential differences at its ends.

        At the heart of the electrodynamic speakers there is a strong permanent magnet, cylindrical in shape, with a cylindrical shaft (the pole) at its centre. Between the pole and the magnet there is a space of a few millimeters, in which a very strong and homogeneous magnetic field exists. The space between the magnet and the pole holds the voice coil. The voice coil is free to move in the magnetic field and supported by an elastic suspension, which makes sure that the coil does not touch the pole, and behaves as if it is floating. When the audio signal in the form of alternating current is conducted through the coil, forces are generated that cause it to move back and forth. On the outside of the coil a diaphragm is attached, the size of which determines the lowest frequency that can be reproduced. The diaphragm moves and sound is generated.

        Larger diameter cones require larger voice coils and magnets. This creates speaker drives with large mass and inertia, which require more power to drive. In an effort to minimize the mass of the diaphragm while keeping the required rigidity, synthetic and sometimes exotic materials are used, such as polypropylene, Kevlar, titanium etc.

        When the cone of a loudspeaker moves forward to impart pressure on the air layers in front of it, then an equal and opposite-directed decompression is created behind it. The low frequencies generated in front of the cone are non-directional and move to cover the area in front and behind the cone. This causes their cancellation, since they interfere destructively with the equal, yet out of phase, low frequencies generated behind the cone.

        The ideal way to avoid this phenomenon is to place the speaker in the middle of a large surface. This is known as an ‘infinite baffle’. Of course, this solution is totally impractical so manufacturers resort to surrounding the speaker with a cabinet. Cabinets are therefore used to support the speaker drives and nullify unwanted cancellations.

        The cabinet design contributes greatly to the response of the loudspeaker and either mimics the free loudspeaker behavior (infinite diaphragm design) or uses the enclosed air to improve performance (bass reflex and acoustic suspension design). The ideal speaker cabinet is rigid so that it does not vibrate from the internal air pressure variations. In addition the cabinet must have significant damping behavior to minimize unwanted sound radiation.

      • What are the ideal properties of materials used to build speaker diaphragms?

        Rigid, yet low-mass materials are ideal for optimal control and sonic accuracy.

        Speaker manufacturers face many challenges in designing speakers. High-frequency reproduction requires fast and accurate diaphragm movements. These diaphragms must have low weight to minimize heat generation and increase speed and control.

        Tweeters, reproducing high frequencies, have low-weight diaphragms and powerful magnets, such as those manufactured from high-density neodymium. Many other materials are used for tweeter diaphragm manufacturing, with aluminum being particularly well suited for this task. They are rigid and low mass, and reproduce fast transients with high speed, accuracy and distortion-free sound. Nomex and silk also make excellent diaphragms.

        Yet low frequencies require large diaphragms that are capable of moving the required volume of air to generate low-frequency sound waves. Large diaphragms weigh more, have greater inertia and decreased sensitivity, while also requiring more power to be set in motion.

        Woofers, reproducing mid and low frequencies, require drivers with larger diaphragms. Kevlar cones are an industry favorite due to their natural mid-range response. Another excellent choice for middle frequency speakers are Alucone® speakers, which have a rigid low-mass aluminum sandwich alloy cone for fast transients, accuracy and distortion-free sound.

        As for the dedicated low-frequency subwoofers, excellent choices for the diaphragm materials are carbon fiber, polypropylene and light but rigid specially-treated paper cones.

      • What is the role of the speaker cabinet?

        The cabinet amplifies the speaker’s output and optimizes specific frequency zones.

        [image]

        When the cone of a loudspeaker moves forward to impart pressure on the air layers in front of it, then an equal and opposite directed decompression is created behind it. The low frequencies generated in front of the cone are non-directional and move to cover the area in front and behind the cone. This causes their cancellation, since they interfere destructively with the equal yet out-of-phase low frequencies generated behind the cone.

        The ideal way to avoid this phenomenon is to place the speaker in the middle of a large surface – known as an ‘infinite baffle’. Of course, this solution is totally impractical so manufacturers surround the speaker with a cabinet. Cabinets are therefore used to support the speaker drives and nullify unwanted cancellations

        The cabinet design contributes greatly to the response of the loudspeaker. It either mimics the free loudspeaker behavior or uses the enclosed air to improve performance (bass reflex and acoustic suspension design). The ideal speaker cabinet is rigid so that it does not vibrate from the internal air pressure variations. In addition the cabinet must have a significant damping effect to minimize unwanted sound radiation.

      • What is 'speaker crossover'?

        The circuit which separates the range of frequencies by the speaker’s woofers and tweeters.

        [image]

        High-frequency reproduction requires fast and accurate diaphragm movements. To increase speed and control, and minimise heat generation, diaphragms must be low weight. Likewise, low frequencies require larger diaphragms, which are capable of moving the required volume of air to generate low-frequency sound waves.

        However, large diaphragms weigh more, have greater inertia and decreased sensitivity, while also requiring more power to be set in motion.

        To overcome the conflicting drive requirements for low and high frequencies, speaker manufacturers resort to two or more designs where dedicated drivers reproduce specific frequencies. This technique requires the use of a crossover circuit, which separates the frequencies and routes them to the appropriate drivers.

         

    • Can Speakers be really… friendly?

      • Why do we need friendly speakers?

        Speaker characteristics directly affect the performance of your Hi-Fi system.

        Speakers are the most critical link between the amplifier, the room and your ears in the music reproduction chain. They carry music from the amplifier to your room and interact with both. Speaker quality and build characteristics directly affect the performance you will get out of your home cinema/Hi-Fi system.

      • How friendly are your speakers to your Amplifier?

        Speakers must ideally match your amplifier, for maximum performance.

        It is widely known that matching speakers with amplifiers is very important if you want to achieve the sound quality that you paid for.

        Even with large and expensive high-end amplifiers, you need sensitive, easily-driven speakers. High-sensitivity speakers reproduce music realistically, without compression or distortions.

      • How friendly are your speakers to your Room's Decoration?

        Beautiful speakers can be placed freely, to achieve maximum sonic performance.

        Most people usually try to hide their speakers, even when these are crafted like expensive furniture that serve our music enjoyment. However, speakers that match your interior décor can be placed according to the laws of electro-acoustics without compromising your style.

        Sound quality is greatly influenced by the position of the speakers in the room. Less expensive speakers correctly placed according to the rules of acoustics will play better than more expensive speakers placed in the wrong position, for example hidden in the corners.

      • How friendly are your speakers to your lifestyle?

        The right speaker must perform equally well with soft music and bombastic action flicks.

        Sometimes all we ask for is background music to a friendly dinner. At other times we are asking for the thrill of a demanding soundtrack or the recreation of a concert in our living room. Our demands from a quality speaker system change depending on our mood, the needs of our busy, varied lifestyles and on the diversity and increasing sophistication of home entertainment technology, like home cinema and games consoles. Crystal Audio speakers are built to satisfy all these needs and more.

      • What is magnetic shielding?

        Your speakers must not magnetically interfere with your sensitive electronic equipment.

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        The magnetic fields generated by the powerful magnets of speaker drivers mean that magnetic shielding is necessary to protect TVs and susceptible magnetic storage media. Speaker magnets are therefore housed in a steal enclosure or a second magnet with reverse polarity is placed behind the speaker to cancel the stray magnetic field.

      • Why can selecting speakers be a challenge?

        Spending money on well known brands, does not guarantee sonic quality and high performance.

        One of the main challenges in setting up a home theatre is choosing loudspeakers. This task is complicated by the incredible variety of loudspeaker brands, models, designs and prices. Spending more money or buying well-known brand speakers does not guarantee that you will purchase the right model. After all, audio experts agree that only a small percentage of loudspeakers are worth buying, and there is often little relationship between performance, brand and price. Within a price range the majority of loudspeakers are underachievers. The rest are good performers and only a select few are star performers.

      • How should I compare speakers?

        Ideally, by following the “blind” test methodology, A-B switching and some reference recordings.

        Comparing speakers can be a fairly complicated procedure. Even a small difference on the sound level can make one speaker sound better than another.

        Do not be fooled into thinking that if you use the same amplifier and keep the volume level constant, the speakers will play at the same level. This is due to the fact that different speakers have different sensitivities to the input signal. Level-matching can only be done with the use of a sound pressure level meter, known as a decibel meter, available from an electronics store.

        It is possible to feed the speakers with white noise, which is included in tracks of special speaker evaluation CDs and DVDs, and match the sound level of the speakers. In an ideal situation the different speakers would be hooked up to an A-B switch that allows the listener to instantly go back and forth between the different models.

        Once the levels are matched it is possible to go on to the next stage of a listening evaluation.

        The tone settings of the pre-amplifier should be set to flat, as we do not want equalization interfering with our evaluation.

        Then, pay attention to how natural the music sounds. Concentrate on the voice of the singer and evaluate how real it sounds. Do the same with musical instruments. Do they sound true? Is the sound balanced, with no artificial emphasis on the bass, midrange or highs? Can you separate the instruments playing? Is the sound focused and the sound image correct? Do the speakers perform well at high and low volume settings? Does the sound stir you emotionally and do you have the feeling of listening to a live performance?

        Once you answer the above questions you will have an excellent picture of the performance of the speakers you are comparing.

      • How should I evaluate speakers?

        By listening to them in an acoustically familiar room and focusing on the different sonic layers.

        Evaluating speakers is really much more difficult than it might initially sound. A whole field of acoustics, namely psychoacoustics, studies the way we perceive sound, decode it in our brain, compare it to realistic sounds and how our auditory perception gets fooled or misled – and not strictly in a bad way! Virtual surround technology is wholly based on the fooling of our auditory perception for a good reason.

        Without getting or even attempting to go really deep into the theory, here are a few general rules:

        - Don't let your other senses, and mainly your sight, intervene in your judgment. Big or good-looking speakers by no means necessarily translate into good sound
        - Consider the room in which you are auditioning the speaker. It is almost impossible to evaluate a speaker in a room you haven't heard music in before
        - Especially in non-acoustically correct rooms the evaluation of speakers is totally unfair
        - The best place to evaluate speakers in is your own listening room. That's why Crystal Audio offers a 60-day trial period during which you can fully evaluate the speakers, trying your favorite music and movies and asking the opinion of your friends and family members
        - Choose reference material (music or movies) and not some average recording. Consult our great Reference Recordings tool and find the best recording of the genre you prefer
        - Try to listen closely to each different layer of sound. Listen to the acoustic instruments, the voice of the singer and evaluate their closeness to reality

        Consider the spaciousness of the sounds, the wideness of the stereo image, the bass quality (tight, bringing music to life or muddy) and the overall experience you get. Close your eyes, immerse yourself in the music and sounds, and feel the emotions triggered from science meeting art

    • All about THX

    • Want to know the basics of THX? Start here & now!

      • What is THX?

        The ultimate set of standards for sonic realism in your Home Theater.

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        THX, the trademark of THX Ltd., is the ultimate set of standards for home theatre sound. It incorporates a series of patented electronic and loudspeaker specifications designed to bring the big theatre experience right into your home.

        THX Certified Home Theatre products deliver cinema-quality picture and Hi-end sound to home environments. Through optimized audio-visual technology and speaker placement, you get a movie experience at home that's as faithful as possible to what the director intended.

        Products certified by THX assure the best possible quality in music and sound reproduction.

        THX Certification is the “seal of approval” for speaker quality. It is the absolute assurance that your loudspeakers will reproduce all music and film material in the way that the composer and film director respectively intended.

      • Why was THX established?

        As a venue design provider for consumer electronics industries.

        THX Ltd. is the founder of quality assurance programs for superior cinema presentation and the leading provider of product certification and venue design for the entertainment and consumer electronics industries.

      • Why choose THX certified equipment?

        To ensure accurate playback as the director or the producer intented.

        To ensure accurate playback as the director or the producer intented.

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        The digital sound formats were developed for movie presentation in cinema settings. Because home environments are different to cinemas, the same THX audio standards that ensure accurate playback in theatres have been adapted for viewing movies in Blu-ray, DVD and broadcast formats at home.

      • What are the benefits of using THX certified equipment?

        Αccurate, trouble-free sound of outmost clarity.

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        Incorporating a variety of digital encoding technologies like Dolby Digital, DTS and PCM, THX Certified Home Theater products offer the most consistently accurate, trouble-free reproduction of sound. THX certified equipment offer comprehensive solutions to multichannel audio formats based on their end to end home entertainment expertise. THX certified equipment ensure:

        - Very clear dialogue
        - Sharply positioned sounds
        - Enveloping surround sound that puts the audience inside a movie
        - Thunderous bass and crystal clear highs
        - Maximum contrast between quiet and loud sounds
        - Smooth and continuous sound movement

      • I have to use a medium that is THX certified, in order to take advantage of a THX certified speaker?

        Νο, a THX certified loudspeaker has the same neutral behavior with any input signal.

        THX Certification has nothing to do with the type or format of the sound information stored in the CD, Blu-ray or DVD. The high standards of a THX certified speaker determine its capability of reproducing crystal clear sound and music. In this way a THX certified loudspeaker has the same perfect behavior in any input signal.

      • Do I need to buy a complete THX Home Theatre system to get the benefits of THX technologies?

        You can use any number of THX home cinema components in any home cinema system.

        Each THX home cinema component - processor, centre speaker, surround speaker, subwoofer, amplifier, Blu-ray player, interconnect, speaker wire, and acoustically transparent screen - solves specific problems in home cinema sound reproduction. You can use any THX home cinema product in any home cinema system. When used all together, these components work synergistically to produce an ultimate surround sound experience.

      • What was the driving force for establishing THX certification?

        The accurate reproduction of film soundtracks in the home environment.

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        The driving force behind the establishment of THX certification was the observation that conventional audio components could not accurately reproduce film soundtracks in the home environment.

        A need to correct the audible tonal and spatial errors caused by the playback of soundtracks designed in and for large cinema in the smaller environment of a home. A need to more accurately reproduce the complex and competing sound fields present in multi-channel sound playback.

      • When was THX certification introduced?

        George Lucas introduced it in 1983.

        Movie cinema THX certification was introduced in 1983. THX certification was developed by director George Lucas, who was dismayed with the sound quality of most cinemas. He felt that all of the directors’ efforts to stir the emotions of the audience with the use of sound and music were undermined by poorly equipped cinemas that reproduced highly distorted sound. George Lucas tasked Tomlinson Holman (then his corporate Technical Director) to develop a set of criteria that cinemas had to meet to guarantee that the soundtrack was played back just as the director intended. These criteria were named Tomlinson Holman eXperiment, or THX for short.

      • When was the home version of THX introduced?

        Domestic THX certification was introduced in the 90s.

        The home version of THX was introduced to the public in 1990. Home THX certification aims to duplicate the THX cinema sound in a home environment. The THX home cinema standard has a firm foundation in the production processes associated with all feature film material.

      • Do all THX home cinema components sound the same?

        No, components do not sound alike.

        The THX standards are a set of minimum criteria that audio components must meet. In addition, there are many different types and levels of THX certification that components can obtain. Manufacturers of home cinema components can differentiate their products by outperforming the minimum standards specified by each certification level and therefore produce components that do not sound alike.

    • Different audio formats and certifications have been confusing you? No more! Read below

      • Is THX a multi-channel sound format like Dolby Digital and DTS?

        No, THX is a set of standards.

        Many consumers erroneously consider THX a multi-channel sound format, similar to Dolby and DTS. THX is a certification program which assures the finest picture and sound quality for cinemas, mixing studios, home cinemas, Blu-rays, multimedia products, and luxury automotive vehicles.

      • Is THX home cinema compatible with Dolby Digital and DTS?

        Yes, THX components process DD and DTS signals normally.

        Absolutely! The goal of THX home cinema is to accurately recreate the experience of the film mixing studio. All mixing studios are capable of creating both 4 and 5.1 channel mixes. The acoustics, equalization curves, and loudspeaker arrays used in a mixing studio remain the same for a digital 5.1-channel soundtrack as they do for a 4-channel Dolby Surround soundtrack. THX home cinema technologies are needed to reproduce these movie soundtracks accurately.

      • What is THX Select?

        THX Select is the THX reference standard for smaller rooms.

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        In the beginning there was only one set of THX criteria for home cinema audio systems, simply known as THX. However Lucasfilm THX realized that its standards had to be differentiated for different size home cinema rooms. THX Select is the THX reference standard for smaller rooms. THX Select criteria are specifically calibrated to define reference level performance in room volumes of about 2000 cubic feet.

         

      • What is THX Select2?

        The THX reference standard for smaller rooms, that specifically addresses receivers.

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        During the CES (Consumer Electronics Show) of 2007, THX announced the THX Select2 certification as an upgrade to the company's THX Select specification for home entertainment products. The new THX Select2 certification provides additional THX listening modes for enhancing playback of a variety of entertainment content, including movies and video games. It specifically addresses receivers, incorporating new features and improved noise floor performance. Based on the same values and principles of THX Ultra2, THX Select2 certified receivers deliver higher quality to smaller home cinema environments.

      • What is THX Ultra?

        The reference level performance for rooms up to 3000 cubic feet.

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        THX Ultra is the original THX home cinema standard. THX Ultra applies more rigorous standards to home cinema components, so that they provide the reference level performance for viewing rooms up to 3000 cubic feet.

      • What is THX Ultra2?

        The ultimate set of requirements for amplifiers and speakers, based on THX Ultra.

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        THX Ultra2 requires amplification for seven channels and stricter requirements for amplifiers and speakers than THX Ultra (Ultra2 specification calls for a subwoofer flat to 20Hz, down from THX Ultra’s 12dB roll-off below 35Hz). The specification also features switchable Boundary Gain Compensation (BGC) that alleviates boomy bass as a result of near-wall listening positions (or, for that matter, subwoofer placement). The Ultra2 processor accommodates both 5.1 EX/ES soundtracks, as well as multi-channel audio recordings by directing ambient sounds to the dipole speakers and discrete effects/sounds to the back channels.

      • What is THX Certified Multimedia?

        A THX certification designed specifically for multimedia.

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        The THX certification for multimedia products aims at delivering cinema-quality picture and sound to the desktop by ensuring that multimedia products comply with THX’s rigorous standards. In other words, the THX certified multimedia stamp is a guarantee that your computer setup is capable of delivering the highest possible fidelity for your MP3s, CDs, DVDs, games, and other digital audio sources, through cinema-quality audio and visual experience.

        Note that THX certified multimedia speakers are not to be confused with THX Select certified speakers, which offer the best quality in a home cinema setup as opposed to more modest computer designs.

    • What are the advantages of THX Certified Speakers?

    • How do THX Technologies benefit my experience?

      • What is THX Re-Equalization?

        The Re-Equalization circuit found in THX processors, removes any accented brightness in soundtracks.

        [image]

        The Re-Equalization circuit found in THX processors, corrects the over-bright sound of movie soundtracks. Movies are mixed in cinemas with a controlled high frequency roll-off, called the "X-Curve". This curve, an international standard, is part of every mixing and cinema's playback system because high frequency roll-off is appropriate for sound sources that are not close. But since home listening distances are shorter, audio mixed under the "X-Curve" sounds too bright when played back through flat response speakers. To match sound for smaller spaces and distances, THX uses a special Re-Equalization Curve, designed for home environments, to restore the correct tonal balance of a movie soundtrack.

        * Image explaining this THX technology belongs to THX Ltd

      • What is the function of Timbre Matching?

        It corrects the surround tonal balance to match that of the front channels.

        [image]

        The THX home cinema Timbre Matching Circuit corrects the surround tonal balance to match the front channels - so what you hear is one smooth, continuous sound field. Surround channels have to compensate for the fact that fewer speakers – typically, two - are used in a home cinema system.

        The first correction is to match the sound character, or Timbre, of the surround channels to the front channels in order to ensure smooth sound movement from front to surrounds. It also realistically places the audience inside the movie experience and not "in-between" two competing sound fields.

        The second correction is to match tone. As sound sources move around the listener (from front to side and behind) the sound can vary in perceived character as much as +8 to -3 dB, even with matched and equalized speakers. This is because sound quality is actually shaped by the human head and outer ear. Our perception of sound quality varies as the source direction changes. (Remember, the tonal quality of sound movement is carefully controlled by the sound mixer.) In a cinema, the speakers are all around your head and are equalized to match the front channels. But if the same soundtrack is played at home, the tonal mismatch is very audible.

        * Image explaining this THX technology belongs to THX Ltd

      • What is Adaptive De-Correlation?

        Adaptive Decorrelation compensates for monophonic surround channels in Dolby Pro Logic.

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        Adaptive Decorrelation compensates for monophonic surround channels in Dolby Pro Logic. In the cinema, this goes unnoticed since the sound is mixed up by the large number of surround speakers and by small room reflections. Your left ear and right ear never get identical sounds, so you never identify the surround sounds as mono. (Even with Dolby Digital and DTS sound and "split" left/right surround channels, mixers use a lot of mono surround sound effects.)

        In a home environment, you’d detect the mono "feel" of the surround channels. In response, the THX Decorrelation Circuit subtly adjusts the time and phase of one surround channel against the other. This constantly changing time and phase differences means that your left ear and right ear never hear identical signals. The sound is never identified as mono and remains spacious, just like in the cinema. For Dolby Digital and DTS split surround signals, an intelligent Adaptive De-correlation circuit de-correlates the surround channels only when it senses mono surround signals.

        * Image explaining this THX technology belongs to THX Ltd

         

      • What is THX Loudness Plus?

        A loudness algorithm for dynamic clarity even at very low listening levels.

        THX Loudness Plus is a new volume control technology with which home cinema audiences can now experience the rich details and ambient sound in a surround mix at any volume level. THX Loudness Plus incorporates two new THX technologies. As you change the volume, THX Multi-channel Spectral Balancingâ„¢ and THX Dynamic Ambience Preservationâ„¢ automatically and seamlessly apply the appropriate compensation. This delivers a more accurate listening experience at any volume level.

        Basically, what it does is to automatically adjust the front-to-back speaker level relationship as you turn the volume level down so that the perceived sounds match as closely as possible the original mix as played back at the reference level (as was recorded and mixed in the studio).

      • What are the THX Surround Sound Modes?

        THX Cinema Mode, THX Games Mode, THX Music Mode, THX Surround EX

        THX Advanced Speaker Array (ASA) recreates the 5.1 studio surround sound field in your home by digitally reconfiguring the surround channels for the type of media you are enjoying. Featured on all Certified Receivers, THX ASA establishes THX Listening Modes, making it convenient to have one speaker set up for movies, music and games. 

        [image]

         

        THX Cinema Mode

        Recreates the ambiance of the movie theater by positioning the 5.1 mix to immerse you in the movie’s soundtrack.

         [image]

         

         

        THX Games Mode

        Distributes the sound effects and dialogue generated by the game engine, placing the audio from a 5.1 mix source to the appropriate “action” location – creating 360-degree gaming experience.

         [image]

         

         

        THX Music Mode

        Emulates the original studio environment by repositioning the 5.1 surround sound mix further behind you for an accurate and increased sense of spaciousness and localization – placing you directly in the recording session.

        THX Surround EX

        Decodes the third surround channel from the traditional two surround channels, creating a more immersive entertainment experience. 

        * Images explaining these THX technologies belong to THX Ltd

    • Setting up a System

    • Confused about connecting your equipment? Here is the place to sort everything out

      • What is an often overlooked link in an entertainment system?

        The right selection and use of interconnects and cables.

        An often overlooked yet important link in a home entertainment system are the interconnects and cables. The right selection and use of interconnects and cables brings out the best performance from any system, while the converse can be a real handicap to your system’s performance.

      • What is the correct way to connect a subwoofer to my system?

        Through an RCA analog audio interconnect.

        Most, in not all, of modern subwoofers are active. That means that they are connected to the receiver with an RCA analog audio interconnect. This is connected to the subwoofer output of the receiver which is basically a pre-amp out signal. In order to enjoy deep bass sound without any hum picked up by the mains (50Hz or 60Hz) or EMI and RFI from the environment, you should pick the best balanced interconnect you can afford. This type of interconnect rejects the common noise between the two cables used to carry the signal, while the outer braid acts as an additional shielding to the cable.

        Furthermore, a sturdy RCA plug should be used to ensure proper connectivity that does not loosen or corrode with time. A locking gold-plated connector is the best choice.

      • How do we hookup speakers?

        Amplifier to speaker hookup is accomplished with good quality speaker wire.

        Basic speaker hookup is very simple. Speakers require a connection to an amplifier. The amplifier might be a separate component, or it might be built into a receiver or integrated amplifier. All amplifiers have output terminals.

        For each channel there will be a positive (red) and a negative (black) terminal. A stereo amplifier will have a left and right set of outputs. It may also have a second set often labeled "B". The "B" output can be used to drive a second set of speakers, for example, extension speakers in the kitchen.

        Amplifier to speaker hookup is accomplished with good quality speaker wire. Most important: Make sure that you connect amplifier positive to positive at the speaker and amplifier negative to negative at the speaker.

        If you are wiring a five or seven channel home-theater system, the principles are exactly the same.

        Note that depending on the length of the cable that you need, you should go for:

        • 16 gauge wire for up to 15m
        • 14 gauge wire for 15m to 30m
        • 12 gauge wire for more than 30m
      • What is speaker phase?

        If the speakers are connected out of phase, you will notice a distinct “gap” in the sonic image.

        When you have more than one speaker, the speakers interact with each other to create a sound field. Sound designers/mixers have the ability to place sounds in various locations within the sound field since they understand the relationship between each speaker. In order for your speakers to faithfully reproduce the sound field, they must all be wired the same way (or in-phase). All negative (-) outputs from the receiver should be connected to the same color (-) input post on each speaker and all positive (+) outputs should be connected to the same color (+) input post on each speaker. If your speakers are out-of-phase with each other, the overall sound will lack the focus and fullness that in-phase speakers reproduce, and you will not hear what the sound designer/mixer intended. Even if only one speaker is wired incorrectly, the sound image will not be correct.

        After we connect our speakers, we are ready to check that the polarity of the connections is correct. If we can not manually check each cable to make sure that the connection is correct, we use an input signal of white noise to be reproduced by the speakers. If the polarity is wrong the reproduced sound will not be focused between the speakers, there will be a distinct hole in the image and a lack of bass. We then need to change the polarity on one of the speakers so that the speakers are in phase.

      • Do both speaker cables need to be the same length?

        Yes, it is best if the cables have approximately the same length.

        If the two speaker cables are not close to each other in DC resistance, and inductance, the damping will be different, and the high frequency roll-off will be different. These kinds of things can affect the stereo image and image depth, as the two channels delicate balance has been disrupted.

        We recommend against any differences in length for shorter lengths of more than a 2-to-1 ratio and preferably the closer to the same, the better. Long runs will be more critical, and would need a closer match still.

      • What is the classic way to connect an audio device to an amplifier?

        Through the analogue or digital inputs.

        The analog inputs and outputs are the classic way to connecting an audio source with the amplifier. We use analog interconnections for the connection of any component (iPods, mp3 players, laptops, turntables, TVs, VCRs, satellite decoders etc.) which does not have a digital audio output.

        However most modern devices offer digital outputs (SPDIF, Optical Toslink or HDMI) for the stereo or multichannel content. In this way, using a quality Digital Coaxial cable, or Toslink Optic fiber or ultimately a version 1.3b Category 2 HDMI cable, you can easily connect audio devices to your receiver without losing any of the quality. Most receivers nowadays decode all audio formats (be it the classis compressed ones, or the latest uncompressed high def Dolby TrueHD and DTS-HD Master Audio), so they can handle the signal processing from the digital field way to the amplified analog end where the speakers are powered.

      • What are the types and advantages of digital connections?

        Digital connections include coaxial and optical, for minimal signal noise and distortion.

        Almost all today's audio/video devices offer a variety of digital connections for the transfer of signal in between them. Digital connections' main advantage is the fact that they are very immune to noise since what really matters is that the source knows if it has received an 1 or 0. After that the signal is reconstructed and fed to DACs (Digital to Analog Converters) so that it is exactly in the form it was produced in the source, without any added noise or distortion.
        The main types of digital audio connections are:

        • SPDIF (Sony/Philips Digital Interconnect Format): Initially used to carry 44.1kHz (CD quality) or 48kHz (DAT quality) and 20bits PCM stereo signal. With the advent of the multichannel era however, the SPDIF protocol adopted the use of compression to transmit multichannel content (Dolby Digital and DTS). Still however it cannot transfer DVD-Audio, SACD and Blu-ray HD audio. The common interconnections utilising the SPDIF protocol are: 75-Ohm coaxial interconnection (RCA plugs), the optical Toslink and the high-end AES/EBU (XLR balanced plugs). Note that basically the SPDIF format is the consumer version of the Audio Engineering Society & European Broadcasting Union (AES/EBU) format
        • HDMI (High Definition Multimedia Interface): The most modern connection that permits to experience the most lifelike picture and sound from today's highest performance displays and sound sources. It carries uncompressed digital data and can interconnect pretty much everything! Blu-ray disc players, PCs, set-top boxes, video game consoles, TVs and A/V receivers. HDMI supports up to 8 channels of audio at sample sizes of 16-bit, 20-bit, and 24-bit, with sample rates of 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz. It supports Dolby Digital and DTS, and up to 8 channels of one-bit DSD audio (used on SACDs). Finally with the version 1.3, HDMI supports lossless compressed audio streams Dolby TrueHD and DTS-HD Master Audio. It also features auto lip-sync (from version 1.3) and certainly caters for video signal transmission above 1080p to 1440p, Deep Color, x.v.Color etc. To make the long story short, it's the best available connection!
        • iLink or Firewire or IEEE1394: Various manufacturers use Firewire, such as the Sony I-Link and the Yamaha mLAN (music Local Area Network) that allows the transport of multichannel digital audio data, control signals and MIDI through one cable to many recipients, aiming to create a home network for the transport of image and audio data similar to computer networks
      • What is all this fuss about different HDMI versions?

        Download the HDMI Specifications table (link herebelow).

        Download the HDMI Specifications table <~FilesVIDEO_AUDIO_HDMI_Guide_(EN).xls> to find out the different features that are supported by each version and category of the HDMI protocol.

      • How to connect my Blu-ray / DVD to my receiver?

        The best way is through an HDMI cable.

        The best way to connect your Blu-ray / DVD to your receiver is by using an HDMI cable. In this way, high definition audio and high-definition video are sent to the receiver, which keeps, processes, amplifies and outputs to the speakers the audio information, while sending the video information to the HDMI out, which should be connected to your TV. This type of connection renders the receiver the controlling point of all the Home Theater system, as by changing the Source setting, both the audio and video are simultaneously selected (for the Blu-ray or DVD source).

        In case your receiver does not decode the high definition audio formats (Dolby TrueHD & DTS-HD Master Audio) you need to let the player do the decoding and instead use high quality audio interconnects (one cable per channel) to transfer the decoded and converted to analog signal, to the receiver. Note that high definition audio is not transfered by Coaxial and Toslink connections due to the very big bit rate that is required. Instead if you connect the Blu-ray using this type of connections, you will only hear the traditional Dolby Digital and DTS compressed audio.

        As for your DVD, if it doesn't feature HDMI, use Coaxial or Toslink to hook it up to your receiver (which in turns does the decoding of the Dolby Digital or DTS stream).

      • What is bi-wiring and bi-amplifying?

        It is a connection that ensures the independent feed of high and low frequencies to the speakers.

        Many speakers, including many Crystal Audio speakers, feature separate binding post pairs for the Tweeter and the Woofer(s). These separate pairs, feeding different crossover parts, isolate the high and the low frequency path of the signal fed to the speakers, Bi-wiring consists in the use of two pairs of speaker cable to connect the two binding post pais to the same output connectors of your amplifier, while bi-amplifying consists of the use of separate amplifier stages to power the high and low frequency sections of the speaker.

        It is rather questionable whether bi-wiring offers a noticeable improvement to the performance of the speaker (other than the increase of the gauge of the cable which in turn reduces losses). Theoretically, it reduces the interaction between the Tweeter and Woofer(s) and improves sound quality.However bi-amping a speakers results in considerable lower intermodulation distortion as a different stage is used for the amplification of the highs and the lows. It is more costly solution but it trully separates the path of high and low frequencies, providing a great clarity to the sound. Note that in order for both bi-amping and bi-wiring to be effective, you should remove the connecting terminals (bridges) that exist between the two binding post pairs of the speakers.

      • What is a balanced connection?

        An analogue connection with conductors for the signal, the inverted phase and the ground.

        An analog connection found in hi-end equipment, which requires three conductors, one for the signal, one for the signal with inverted phase and one for the ground. Balanced connections use three-conductor connectors, usually the XLR or TRS jack plug. The term "balanced" comes from the method of connecting each wire to identical impedances at source and load. This means that much of the electromagnetic interference will induce an equal noise voltage in each wire. Since the amplifier at the far end measures the difference in voltage between the two signal lines, noise that is identical on both wires is rejected. The noise received in the second, inverted line is applied against the first, upright signal, and cancels it out when the two signals are subtracted.

        Balanced connections should absolutely be prefered for the Subwoofer, which is prone to low frequency noise that results in an audible hum.

    • How can I choose the best Receiver (amplifier) for me?

      • Which is the best-suited amplifier power for my loudspeakers?

        All of Crystal Acoustics’ loudspeakers declare their "recommended amplifier power" spec.

        Amplifier and loudspeaker power ratings are specified differently. For amplifiers, the output power is specified on the basis of an undistorted continuous sine signal; for loudspeakers, the (long-term) power handling is specified on the basis of a noise signal shaped in accordance with the standard frequency distribution of a music signal. The respective peak values are twice as high with sine signals, but at least four times as high with noise signals. Over a short period of time Crystal Audio loudspeakers can handle levels distinctly above the norm power specification. Amplifiers, however, can supply only a little more than their nominal power even over a fairly short period of time, after which clipping will set in. Amplifier power and loudspeaker power handling thus cannot be related exactly. To define a reasonable speaker/amplifier combination, all Crystal Audio loudspeakers are specified with a "recommended amplifier power". The lower value marks the minimum amplifier power for achieving slightly more than moderate volume levels under typical listening conditions. The upper value guarantees that even at the highest volume levels that are suitable for the loudspeaker, the amplifier signal will be clipped only rarely. However, due to the varying nature of audio signals, these are only general suggestions to be adjusted according to your system.

      • What amplifiers do you recommend?

        You should opt for the most powerful amplifier you can afford, based on your needs.

        Crystal Audio does not recommend any particular brand of amplifiers. The choice of an amplifier is a personal matter dependent on taste, power handling, how many speakers are being used, what type of features you need and of course what your budget is.

        However, we can give a few hints on what to look for when selecting your Amplifier/Receiver. Speaker Amplifier requirement figures (Watts) are intended only as a guide.

        As a rule, buy the most powerful amplifier that you can afford within the specified range and use it with great care. It is easier to damage the loudspeaker with a small amplifier driven into distortion using too much volume with bass and treble boost, than with a large amplifier, which has plenty of power in reserve.

        In addition, check whether the receiver offers Auto-Calibration (it is strongly suggested for inexperienced Home Theatre users). In addition, can it decode today's high definition audio formats (Dolby TrueHD, DTS-HD Master Audio, etc.), and does it support HDMI connectivity and offer upscaling for video signals?

        We recommend that you discuss with your local specialist hi-fi dealer what they would recommend as they have firsthand knowledge of what systems work best with room layouts, sizes and shapes.

      • What happens if the amplifier power rating is less than the power handling of the speaker?

        There is a chance that you may cause severe damage to the speakers.

        If the amplifier’s power rating is below that of the speaker, the amplifier will try too hard to keep up with the speaker, which means that here is danger that the amplifier will "clip" which could possibly cause damage to the tweeters or destroy the speakers.

      • Is it advisable to buy a receiver (multi-channel amplifier) even for a stereo configuration?

        Yes it is! The added benefit is that you can upgrade your system any time!

        Yes it is! If you use modern, stylish and compact speakers for the Left and Right channels, then you most probably need a Subwoofer to add the bass frequency extension needed to get a realistic music reproduction. Classic stereo amplifiers do not support the connection of a subwoofer, while modern receivers offer a subwoofer output, plus electronic crossovers for the proper bass management. Set the crossover frequency to 80Hz (if your main speakers are able to reproduce those frequencies) and set the levels of main speakers and sub, so that the result is balanced.

        However, note that it is not only about having small speakers. Even if your speakers can reproduce low frequencies, the bass management can only be optimum if you can isolate them and place the speaker reproducing them (here comes the Sub!) in the best position according to room acoustics (where the standing waves are less prominent so that the low frequencies sound field is smooth). Otherwise, you will be obliged to keep the low frequencies tied to the main speakers, whose position is strictly specified and not flexible like the subwoofer's.

        Apart from that, you get a mult-ichannel receiver and have the added bonus of being able to upgrade to a 5.1 or 7.1 system at any time you wish.

      • What does DSP mean?

        It means Digital Signal Processing.

        The letters DSP stand for Digital Signal Processing. The signal is the information that is picked up from the Blu-ray, DVD or CD, flows through the system, and eventually emerges as music or movie soundtrack.

        Signal processing refers to just about everything your sound system does to your signal -- anything from raising it from a preamp to an audible level, to boosting or cutting bass and treble, all the way to making your living room sound like a stadium or a movie theatre. Digital Signal Processing performs that type of signal manipulation in the digital domain.

        That is, it deals with your signal not as a continuous stream but as a series of "zeros and ones". DSP’s most common applications used to be the re-creation of various acoustic environments in our living room, so we can listen to Miles Davis play in a "jazz club" and the Benedictine Monks chant in a "cathedral". Nowadays, more sophisticated DSPs decode the multichannel high definition formats and calibrate automatically your speakers' response so that their in-room performance is balanced.

      • Why does my AV Receiver decoder provide delay adjustment?

        It adjusts the audio delay between different distanced loudspeakers in your setup.

        Because the speakers in a home theatre system are all at a different distance to the viewers, multi-channel playback requires a delay of the signal reaching them, in order to virtually align the speakers, so that they are equidistant to the listener. This delay is inserted to the receiver via the distance of each speaker from the main listening position. Note that this is mostly done automatically in modern Auto-Calibration receivers, using their calibration microphone. By inserting the correct delay times needed, the carefully created sound stage is accurately rendered.

      • What does the Auto-Calibration function of my receiver do and how does it affect of my speakers?

        After completing the process, levels and distances of speakers are spot-on.

        Most modern receivers feature an Auto-Calibration function (be it Audyssey technology on Denon and Onkyo designs, Sony's Digital Cinema Auto Calibration, Pioneer's Multi Channel Acoustic Calibration or Yamaha's Parametric Room Acoustic Optimizer). Basically you set a microphone (provided with the receiver) where one of the ears of the main listener would be and the receiver outputs a series of signals (mostly noise bursts) to all of your speakers, setting their levels, distance from listener, confirms their correct phase and finally tries to correct through equalization either the non-flat response of speakers themselves or the combined effect of room acoustics with your speakers that results in uneven response. The series of tests from the receiver may be repeated for more microphone positions, depending on the Auto-Calibration algorithm implementation, resulting in more uniform reproduction across a wider area as opposed to a confined sweet spot.

        Most probably, the levels and distances of speakers are spot-on after the Auto-Calibration is finished. However, check to see that the figures seem reasonable. As for the frequency correction performed through EQ, do not always assume that it gives a better result. Be sure to listen your system using your favourite music and movies and turn the Auto-Calibration EQ on and off periodically to see what sounds best to your ears. If on the other hand you are an experienced Home Theatre user, really striving for the best result, you can fine tune the EQ settings using your ears (NOT advised!) or a SPL-meter together with a DVD that provides band filtered noise, enabling you to measure the SPL produced by your speakers for some split bands of the 20Hz-20kHz spectrum.

      • What are the technical characteristics of an amplifier that can drive low impedance speakers?

        It must be able to transform PCM to PWM and amplify them effectively in the digital domain.

        The size of the capacitors and the transformer utilized in the power supply section and the implementation of the amplified stages determines the capability of the amplifier to drive low impedance speakers.

        The most critical factor is the amplifier capability to increase the output current that it can supply to the speakers. Amplifiers with carefully implemented power supplies, large transformers and capacitors, do not run out of the power required to deliver the sound accurately.

        If the amplifier cannot supply the required current, then the sound of the system will be inferior and could even damage the speakers.

        Weak bass, reduced dynamics and harsh highs characterize the sound of a system whose amplifier is not up to the task. Especially dangerous for the speakers is the occurrence of "clipping". In general, all semiconductor amplifiers can drive any speaker as long as it is not clipping.

        Today's receivers, on the other hand, offer protection so that they don't result in clipping even if the connected speakers have quite a low impedance.

      • What are digital amplifiers?

        Amplifiers made of capacitors, transformers and amplifier stages.

        The audio sources of home entertainment systems are becoming increasingly digitally based. This has increased the popularity of digital power amplifiers. There are two methods for engineering a digital amplifier: true digital power amplifiers and power amplifiers which incorporate digital technology. The latter type accepts a digital signal at its input which is then converted to an analogue signal by its integrated Digital to Analogue (D/A) converters, and is amplified in the traditional analogue way. As for the first type (a true digital amplifier or class D design), they transform the incoming PCM (pulse code modulation) audio signal, into another digital format called PWM (Pulse Width Modulation), which is then amplified in the digital domain. The PWM amplification stage is a type of switching circuit, and is therefore not influenced by nonlinearity and transistor noise. The PWM data switches conventional transistors on and off depending on the length of the data pulse. The signal amplitude depends on how long the transistors are on or off. The on/off output of the transistors represents the audio wave. At the final stage, the PWM amplified signal is lowpass filtered (using a high quality coil-capacitor network), so that only audible frequencies pass through while all the high frequency content is rejected.

    • Should I fill up my living room with cables to enjoy performance Home Theater?

      • What happens if connecting my Surrounds would create a cable clutter?

        Check out our Wireless Amplifiers!

        It is true that the Surround speakers are the hardest to be wired. Since your receiver is from the opposite direction (somewhere near the Center speaker) you must have two cables running across your room to feed signal to the rear speakers. Of course your electrical installation may have provided for pre-installed cables inside the walls so your problems end here!

        On the other hand if it is really difficult to hook up your Surrounds without causing a mess with cables, you can simply check our Wireless Amplifiers. Simply connect the wireless trasmitter to your amplifiers Surrounds output (high level or pre-amp level) and then just plug the wireless receivers with integrated amplifiers, to an outlet on the wall where your surrounds are, and connect them with small cables to your speakers. It's as simple as that. Go to the Wireless Amplifiers page for more information.

      • What are the advantages of using Wireless Amplifiers for my Surrounds?

        You can install the speakers without any cables crossing your room.

        Obviously you install rear speakers without any cable crossing your room. That alone is a great benefit, ain't it? Apart from that however, the Wireless Amplifiers offer another great advantage. They relieve the burden from your main A/V receiver of powering the rear speakers, thus leaving more power and headroom for the front and center speakers to perform optimally even if their impedance is quite low.

        And all that without any trade off. The sound delay inserted by the wireless transmission is totally undedected by human ear (around 2ms) and the transmission is totally noise and interference prone free.

      • Are the Crystal Audio Wireless Amplifiers prone to interference from other wireless devices?

        No, thanks to the advanced filtering circuit.

        No. The transmission along with the correction algorithms used support an interference free operation, immune to mobile and wireless phones, microwave ovens, wireless computer networks, Bluetooth devices, human body, etc. Additionally, the four channel auto-detection and auto-scanning feature ensures that a free band is always selected automatically when you are in a really 'electomagnetically noisy' environment, without you having to worry about changes switches.

      • Can I use the Crystal Audio Wireless Amplifiers to power up other speakers apart from the Surrounds?

        Of course you can.

        Surely you can. You can use them to power up a pair of stereo speakers in your balcony or your garden. You can also use the Wireless Amplifiers to connect your iPod or mp3 player or Laptop to feed music to your Hi-Fi speaker pair without any annoying cables lying on the floor. Or you can send music to another room(s) buying some extra Wireless Receivers. The possibilities are really endless!

      • What type of signal transmission is used by the Crystal Audio Wireless Amplifiers?

        DSSS (Direct-sequence spread spectrum) Wireless Digital Transmission.

        The Crystal Audio Wireless Amplifiers utilize DSSS (Direct-sequence spread spectrum) Wireless Digital Transmission for Class-leading, Uncompressed CD-quality signal. The band used is the ISM at 2.4 GHz. It supports a data rate up to 4Mbps. It's an interference-free transmission, immune to mobile and wireless phones, microwave ovens, wireless computer networks, Bluetooth devices, human body, etc.

    • What are the mostly used audio formats?

      • What is THX?

        The ultimate set of standards for sonic realism in your Home Theater.

        [image]

        THX, the trademark of THX Ltd., is the ultimate set of standards for home theatre sound. It incorporates a series of patented electronic and loudspeaker specifications designed to bring the big theatre experience right into your home.

        THX Certified Home Theatre products deliver cinema-quality picture and Hi-end sound to home environments. Through optimized audio-visual technology and speaker placement, you get a movie experience at home that's as faithful as possible to what the director intended.

        Products certified by THX assure the best possible quality in music and sound reproduction.

        THX Certification is the “seal of approval” for speaker quality. It is the absolute assurance that your loudspeakers will reproduce all music and film material in the way that the composer and film director respectively intended.

      • What is the difference between Dolby Pro Logic, Dolby Pro Logic II and Dolby Digital?

        They are different audio processing and discrete signal technologies from Dolby Digital.

         

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        Dolby Pro Logic is a matrix decoder that decodes the four channels of surround sound from a Dolby Matrix encoded stereo track, such as VHS HiFi tapes, Stereo CDs, etc.

        [image]

         

        Dolby Pro Logic II is an advanced matrix decoder that derives five-channel surround (Left, Center, Right, Left Surround, and Right Surround) from any stereo track. It works on any file even if it hasn't been encoded in the Pro Logic II format. On encoded material such as movie soundtracks, the sound is more like Dolby Digital 5.1 (see below), while on unencoded stereo material such as music CDs the effect is a wider, more involving soundfield. Among other improvements over Pro Logic, Pro Logic II provides two full-range surround channels, as opposed to Pro Logic’s single, limited-bandwidth surround channel.

        [image]

         

        Dolby Digital 5.1 on the other hand is a discrete system that keeps the multiple 5.1 channels fully separated throughout the encoding and decoding processes.5.1-channel soundtracks can be heard on most movies either on DVDs or in theatres. Dolby Digital 5.1 is also being offered through Window Media 9, digital cable, digital broadcast TV (DTV), and satellite transmissions. Dolby Digital needs to be decoded by a Dolby Digital Decoder. It does not use the same Dolby Surround encode/Pro Logic decode process. Though you can listen to Dolby Digital 5.1 Encoded soundtracks in Dolby Pro Logic via the analog outputs on most DVD Players. In addition to having full-range Left, Center, Right, Left Surround, and Right Surround channels, Dolby Digital 5.1 soundtracks carry a sixth (“.1”) channel recorded with low-frequency effects (those bass rumbles and booms you feel as well as hear in a well-equipped cinema).

      • Do all Dolby Digital programs provide 5.1 channels?

        No, Dolby Digital soundtracks can provide anything from mono to full 5.1-channel surround sound.

        No, Dolby Digital soundtracks can provide anything from mono to full 5.1-channel surround sound. DVD discs can even carry multiple versions of the soundtrack that differ in the number of channels.

        A disc might contain a 5.1-channel sound mix with the dialogue in one language, a Dolby Surround-encoded two-channel mix in another language, and a mono track with the directors’ comments or other supplementary information.

        The default soundtrack will vary from disc to disc, so always check the DVD disc’s Language menu for the choices offered.

      • What is DTS?

        DTS, much like Dolby Digital, is a high bitrate audio technology for Home Theater sound

        [image]

        DTS (Digital Theater Systems) is the alternative to Dolby Digital when it comes to digital surround sound. Like Dolby Digital, DTS is a discrete digital multichannel audio format.DTS is most often associated with movie soundtracks, but this high-resolution approach to surround sound is also being used to create multichannel versions of music recordings, too.

        Whether we're talking about a movie theater or a home theater, DTS, like Dolby Digital,is an encode/decode system: to play back a Dolby Digital soundtrack, you need a Dolby Digital decoder, and to play back a DTS soundtrack you need a DTS decoder.

      • What is Dolby Digital?

        An advanced form of digital audio coding for high-quality digital surround sound.

         

        [image]Dolby® Digital technology is an advanced form of digital audio coding that makes it possible to store and transmit high-quality digital sound far more efficiently than was previously possible. First used in movie theaters in 1992, Dolby Digital technology is the result of decades spent by Dolby Laboratories developing signal-processing systems that exploit the characteristics of human hearing.

        Dolby Digital programs can deliver surround sound with up to five discrete full-range channels: Left, Center, Right, Left Surround, Right Surround-plus a sixth channel for powerful low-frequency effects. As it needs only about one-tenth the bandwidth of the others, the LFE channel is referred to as a ".1" channel (and sometimes erroneously as the "subwoofer" channel).

         

      • What are the different types of DTS and Dolby Digital audio formats?

        DTS-ES, 96/24, DTS-HD High Res, DTS-HD Master Audio, Dolby Digital, Dolby Digital EX, Dolby TrueHD

        The different types of DTS formats are:

        • Standard 5.1 channel DTS Surround decoder

        • DTS-ES (DTS Extended Surround) including two variants, DTS-ES Matrix and DTS-ES Discrete 6.1. The latter provides 6.1 discrete channels, with a discretely recorded (nonmatrixed) center-surround channel, while the first one provides 5.1 discrete channels, with a matrixed center-surround audio channel

        • DTS Neo:6, like Dolby's Pro Logic IIx system, can take stereo content and convert the sound into 5.1 or 6.1 channel format

        • DTS 96/24 allows the delivery of 5.1 channels of 24-bit, 96 kHz audio and high quality video on the DVD Video format. It can also be placed in the video zone on DVD Audio discs, making these discs playable on all DTS-compatible DVD players

        • DTS-HD High Resolution Audio, along with DTS-HD Master Audio, comprise the DTS-HD extension to the original DTS audio format. It delivers up to 7.1 channels of sound at a 96 kHz sampling frequency and 24-bit depth resolution. DTS-HD High Resolution Audio is selected as an optional surround sound format for Blu-ray Disc and HD DVD, with constant bit rates up to 6.0 Mbit/s and 3.0 Mbit/s, respectively. It is supposed to be an alternative for DTS-HD Master Audio where disc space may not allow it

        • DTS-HD Master Audio supports a virtually unlimited number of surround sound channels, can downmix to 5.1 and two-channel, and can deliver audio quality at bit rates extending from DTS Digital Surround up to lossless (24-bit, 192 kHz). DTS-HD Master Audio is selected as an optional surround sound format for Blu-ray and HD DVD, where it has been limited to a maximum of 8 discrete channels. DTS-HD MA supports variable bit rates up to 24.5 Mbit/s on a Blu-ray Disc and up to 18.0 Mbit/s for HD DVD, with two-channel encoded at up to 192 kHz or 8 channels encoded at 96 kHz/24 bit

        The different Dolby Digital formats are:

         

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        Dolby Digital is the common version containing up to six discrete channels of sound

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        Dolby Pro Logic IIx technology lets you take your listening environment to the next level by expanding your two-channel (stereo) or 5.1-channel audio to 6.1- or 7.1-channel playback. Dolby Pro Logic IIx also extends Dolby Pro Logic's sophisticated technology for the smoothest surround sound experience possible.

        [image]

         

        Dolby Pro Logic IIz takes surround to the next level by adding front height channels—an additional pair of speakers positioned above the front left and right speaker. What that means for you is a surround sound experience with incredible depth and dimension. Most surround sound solutions use digital signal processing (DSP) to artificially model listening environments. Expanding on proven Dolby Pro Logic IIx technology, Dolby Pro Logic IIz stands apart by identifying and decoding spatial cues that occur naturally in all content—stereo and 5.1 broadcast, music CDs, DVDs, 5.1- and 7.1-channel Blu-ray Discs, and video games. It then processes ambient sound and certain amorphous effects such as rain or wind and directs them to the front height speakers.

        [image]

        Dolby Digital EX is similar in practice to Dolby's earlier Pro-Logic format, which utilized matrix technology to add a center channel and single rear surround channel to stereo soundtracks. EX adds an extension to the standard 5.1 channel Dolby Digital codec in the form of matrixed rear channels, creating 6.1 or 7.1 channel output

        [image]

        Dolby TrueHD, developed by Dolby Laboratories, is an advanced lossless audio codec based on Meridian Lossless Packing. Support for the codec was mandatory for HD DVD and is optional for Blu-ray Disc hardware. TrueHD supports 24-bit, 96 kHz audio channels at up to 18 Mbit/s over 14 channels (HD DVD and Blu-ray Disc standards currently limit the maximum number of audio channels to eight). It also supports extensive metadata, including dialog normalization and Dynamic Range Control

        [image]

         

        Dolby Digital Plus gives you access to more content and lets you experience all of the enveloping surround sound that Blu-ray Disc™, high-definition (HD) broadcast, and streamed and downloaded media make possible. Enables up to 7.1 channels of theatre-quality sound, unlocking the full audio potential from Blu-ray Discs, HD broadcast, and streamed and downloaded media. 

      • Are Crystal Audio speakers suitable for playback of Dolby TrueHD & DTS-HD Master Audio formats?

        They are perfectly up to the task!

        Of course. Not only they are suitable for High Definition audio formats however, but they are indispensable to get the best out of them. These High Definition audio formats simply deliver discreet uncompressed audio, coded using extremely high bit rates, for all the channels of a modern multichannel system. The result is that you can hear (if your system permits it!) all the details that the director and musicians wanted to breath into their creation. These details and depth are perfectly rendered by the Crystal Audio speakers.

        Bottom line: The new HD audio formats are useless if your speakers are not so good as to reveal their depth!

      • What type of connection is needed to enjoy the new High Definition audio formats?

        HDMI is the best possible choice offered by current standards.

        [image]

        The new High Definition audio formats use extremely high bit rates to transmit the massive amount of data needed to decode the information for all channels of a multichannel system. Thus, conventional connections like the SPDIF/Toslink are rendered pretty useless. Thanks to the HDMI however (note, it must be version 1.3) the connection of HD sources to your A/V receiver is as easy as plugging one cable. Alternatively you can transfer the signal in the analog field, using one, high quality, audio interconnect per channel. The use of a quality HDMI, version 1.3, is highly proposed though.

    • Room Acoustics

    • How should my listening room ideally be?

      • Does the size and shape of my room affect the set up of my surround sound system?

        There is a direct correlation between your room’s size, shape and loudspeaker placement.

        There is a direct correlation between your room's size and shape and the placement of your speakers. In a "long" room set-up, with the seating located in the middle of the room, it is best to mount the surround speakers on sidewalls parallel to the main seating position. If they were mounted on the rear wall in this room configuration there may be a pronounced "hole" in the sound stage, with sounds "jumping" from front to rear rather than there being a smooth transition. In a "short" room set-up with seating on the rear wall you might get away with speakers being mounted on the rear wall. Furthermore, depending on the distance of the side walls from the listener, you might prefer to use floorstanding speakers as surrounds instead of dipoles.

      • What are the steps for the correct selection of speakers that match your space?

        Decide which stereo or multichannel system you like best and run our RAD on-line application.

        Only by selecting the proper speakers for your room you will have high quality sound. Do you need a simple stereo or a modern multichannel system? Keep in mind that modern multichannel home cinema systems are good not only for movie reproduction but also for high quality audio reproduction - SACD (Super Audio CD), DVD-Audio - as well as modern games consoles such as the X-Box and Playstation. You can listen to your favorite albums in a multichannel mix and feel a truly new experience.

        Once you decide on a stereo or multichannel system (we recommend a modern multichannel system), consult the Crystal Audio Room Acoustics Designer - RAD®, a unique utility which helps you place your Home Theater in the optimum way into your own room. You can choose different types of speakers, according to your preference and room dimensions. At the same time you will be properly consulted for the correct placement of the speakers in the room based on the room dimensions, furniture etc.

        Room Acoustics Designer® is more than a simple programme that selects loudspeakers based on the input of the user.

        • It takes into consideration the furnishing of the room and the dimensions of the video display or TV, to place the loudspeakers in optimal locations
        • It offers the suggestions to the user in a friendly graphical way
        • When the user changes the listening position, then simultaneously all the components of the system (display, speakers) are moved, so that the acoustic rules are followed

        Room Acoustics Designer® is a patented software, accessible free of charge at the Crystal Audio website.

      • What are the standing waves or room modes?

        When a wave hits a solid boundary (e.g a wall) it gets reflected, causing a so called “standing wave

        When a wave hits a hard boundary (in our case the wall/floor/ceiling of a room) it is reflected back. The reflected wave adds with the original wave and depending on the ratio of the wavelength to the dimensions of the room, the sum of the two waves creates points in the room where specific frequencies are emphasized and points where they are attenuated. The result from the wave sum is called standing wave, as it does not propagate in space but rather creates a 'standing' field that selectively boosts and attenuates different frequencies. An alternative naming for this phenomenon is room modes, where each mode represent the standing wave that is caused by each separate boundary and affects a specific frequency.

        In the end of it all the multiple reflections result in different frequencies being boosted or attenuated by a different amount in different places in the same room, all depending on the position of speakers.

        For typical 'small' domestic listening rooms, low frequencies are the ones affected my this wave effect. Hence the attention we must pay in correctly placing the subwoofer in the room so as to minimize the standing waves.

      • What are the ideal room dimensions for best speaker performance?

        You must work with the room available to you.

        Rooms with different height, width and length are preferable for best low frequency performance and for the minimization of resonance problems, but obviously you must work with the room available to you. If possible, place the speakers so they are firing along the longest wall. In other words, if the room is 5 meters wide and 10 meters deep, place them along the 5-meter wall. There will be less wall reflection and therefore a more natural sound.

      • What rules to follow for a home theater room construction?

        Room shape, reflections, reverberation time and isolation, are key elements you must consider.

        When building a new home theater room or renovating an old room, here are some good rules to follow:

        • Shape has direct effect on sound quality. One dimension should not be divisible by another, for example 4 x 8 x 15 is bad, while 4 x 9 x 15 is good
        • Stick with rectangular rooms, which minimize wide-open archways into adjacent rooms. Irregularly-shaped rooms do not avoid standing waves; they simply make them harder to predict and minimize
        • Avoid any concave curved shapes as they focus sound reflections
        • Control sound reflections and echoes with the use of absorption or diffusion materials
        • Control reverberation times using the right absorption
        • Good sound isolation allows use of the room anytime, and minimizes background noise
      • What are the realistic Sound Levels that you need in your Space?

        They range up to 194dB SPL! Check the following table.

        The table that follows indicates the Sound Pressure Levels dB SPL, of various sound sources. It helps you realize yor requirements in sound level.

        • Rocket 194 dB
        • Jet engine 160 dB
        • Propeller Airplane 140 dB
        • Pain Threshold 135 dB
        • Jets' take off (60m) 120 dB
        • Closed off space with Loud music 115-120 dB
        • Symphonic orchestra 113 dB
        • Piano solo (peak RMS, 1/8sec) 110 dB
        • Piano solo 103 dB Large truck 100 dB
        • Minimum audio level for Hi-Fi system evaluation 96 dB
        • Noisy office 80 dB Train (30m) 70 dB
        • Vacuum cleaner (3m) 70 dB
        • Speech (30cm) 70 dB
        • Conversation 60 dB
        • Secluded office 50 dB
        • Quiet residence 40 dB
        • Recording studio 30 dB
        • Rustle of leaves 20 dB
        • Limit of hearing 20 dB
      • Which combination of Amplifier/Speaker/Room give the dB that you require?

        According the table below.

        The table below indicates the Sound Pressure Level of a pair of speakers with 90 dB/2.83V/m sensitivity and 8Ohm impedance. Note that a stereo pair produces 90 + 3 = 93dB of SPL, that is a 3dB increase (as opposed to +6dB which you would be inclined to think).

        Distance

        Power

        1m

        2m

        4m

        8m

        1W/ch

        93

        87

        81

        75

        2W/ch

        96

        90

        84

        78

        4W/ch

        99

        93

        87

        81

        16W/ch

        102

        96

        90

        84

        32W/ch

        105

        99

        93

        87

        64W/ch

        108

        102

        96

        90

        128W/ch

        111

        105

        99

        93

        256W/ch

        114

        108

        102

        96

        Using the 3 rules of calculation of the sound level, you can calculate the SPL of your speakers for various distances and amplifier output power depending:[image]

        • On the distance of speakers and listener:

          • Doubling the distance results in a 6dB reduction of the sound level

          • At half the distance the sound level is increased by 6 dB

        • The sensitivity of our speakers:

          • Two speakers deliver 3dB more than one speaker

        • The impedance of the speaker:

          • The sensitivity is expressed in dB at 2.83V (modern amps are constant voltage sources), which is equivalent to 1Watt at 8Ohm. If the impedance is different than that, ie. 4Ohm, the sensitivity will correspond to a power of 2Watts (P=V2/R, so P=2.832/4=2W), hence the SPL will be half (-3dB) at 1Watt. Download the simple Sound Pressure Level calculator and insert the exact sensitivity & impedance of the speakers you intend to buy and find out the produced SPL at different distances and for various amplifier powers, for a Stereo pair

        • The power of our amplifier:

          • Twice the power (watt) results in a 3dB increase of the SPL (under the assumption that the speakers can handle the extra power without distortion or damage)

        [image]

      • What is Room Equalization?

        An audio correction algorithm to counteract the effects of room resonances and standing waves.

        No matter how careful the design of the home theater room is, there still exist standing waves and speaker/room boundary interactions. In both circumstances a proper equalization can restore accurate spectral and tonal balance. During the 60’s and the 70's graphic equalizer use (or shall we say abuse) resulted in highly unsatisfactory sound. Equalizers were used for everything from tone controls to means of forcibly obtaining flat frequency response from grossly inaccurate loudspeakers and in the process lost their appeal with the audiophiles. Today, sophisticated algorithms, implemeted by some niche manufacturers, provide corrections both in frequency and the time field (that is they correct the frequency response as well as the phase of the waves) resulting in a much better (although still not perfect) undoing of the effects of the room acoustics.

    • How to place my speakers?

      • Where is the best place for my surround sound speakers?

        The best placement is between 90° to 110° from each side of your listening position.

        [image]

        The best surround speakers are Dipoles. Their role is to offer a wide dispersion of sound in all directions, giving benefits such as a transparent and detailed sound and rear channel effects that are similar to a true cinema experience, created by the rows of side loudspeakers.

        The best placement of Dipoles are between 90° to 110° to each side and about 70cm or higher above the listener's ears.

         

      • Placement of the Main Speakers

        Please refer to the drawing.

        [image]

        • The greater the distance of the speakers from the walls the better their response

        • Place the main speakers slightly in front of the TV and not at the same line with it, so that he distance of the main speakers from the listening position is identical to that of the center speaker. Placing the speakers this way also reduces the reflections from the TV screen

        • The speakers must form an isosceles triangle with the listening position. The speakers are placed in font of us just like a live orchestra

        • The greater the distance between the main speakers, the wider is the stereo image that we get. However we must be careful not to place the speakers too far apart, or we will create an acoustic hole between them

        • The tweeter must be placed at the ear level when seated at the listening position an there should be no objects in the direct path of the sound to our ears

        • Slightly turning the speakers towards the listening position improves the sound focus but it reduces the dimensions of the sound image. This affects some speakers more than others. Trial is the best way to determine this...

        • All speakers must be broken in for some time. Use your speakers for at least for 100 hours in mid to low listening levels, before they can perform at their best.

      • Placement of the Center Speakers

        Please refer to the drawing.

        [image]

        • Align its facade with the TV screen, to reduce diffraction. Diffraction is the secondary sound generated when sound meets a discontinuity

        • If the speaker is placed below the TV, tilt it upwards, towards the listeners. If it is placed above the TV, tilt it downward towards the listeners

        • Make sure that the central speaker is not placed above or below the tweeter level of the main speakers by more than 60-70 cm

      • Placement of the Surround Speakers

        Please refer to the drawing.

        [image]

        • The reflections from the Surround speakers are useful, in reverse of the reflections of the main speakers that are destructive to the sound quality

        • The tweeter must not aim at your ears

        • The sound must be directed towards a wall so that it reaches our ears after a reflection

        • It is preferable that they are placed at least 50 cm above the ear level of the seated audience

      • Placement of the Subwoofer

        Experiment with various locations based on herebelow suggestions

        The successful placement and adjustment of a subwoofer is the result of many trials. A correctly placed and adjusted subwoofer generates sound that cannot be localized as coming from a separate speaker.

        Place the subwoofer near the listening position. Play a jazz piece with acoustic bass and many succeeding notes "walking bass". Get down on your knees (beware of your neighbors...) and find the exact point of the room where the bass sounds the clearest. Now change position, place the subwoofer at this spot and sit at your listening position.

        Avoid placement of the subwoofer equidistant from the two walls. If, for example, the width of the room is 8 m, do not place the subwoofer at the middle of this distance (4 m).

        Do not place the subwoofer in the corner and at the same distance from the two corner walls.

        Place the subwoofer as close to the listening position as possible. This way you will experience more of the direct sound of the subwoofer instead of the reflections of the room.

        The use of two subwoofers, to the left and to the right of the listening position, is the ideal albeit more expensive solution.

        The ideal location for the subwoofer may not be practical. Think of the decor of the room and make sure the subwoofers are not in the way.

        Experiment with various locations based on the above suggestions. You will be rewarded with much better sound without additional cost.

      • What is the benefit of using two or even four subwoofers?

        You will enjoy uniform, fully extended low frequencies with minimal to none standing waves.

        Extensive THX and AES (Audio Engineering Society) research has proven that the use of two and - even better - four subwoofers is the best solution for achieving a uniform bass performance for many seats around the listening area.

        Each subwoofer creates its own modes, which overlap randomly with the modes of the other subwoofers in the room. Statistically, this results in a more uniform result, with the big dips and peaks in the low frequency response being mitigated considerably.

        Overall, the use of at least two or even four subwoofers, leads to the following advantages:

        • Significant alleviation of room resonances
        • Enhanced low frequency coverage
        • Even excitation of all modes in the listening area, not just for the main listening position
        • Significant reduction of the frequency variations from seat-to-seat
        • Effective equalization over a wide seating area, rather than a small sweet spot or even a single listening position

        For the ones craving the most realistic LFE experience, the extra cost is definitely worth the effort!

    • Power (Wrms) 150
    • Maximum Power (Watt) 300
    • Sensitivity (dB/2.83V/m) 91
    • Impedance (Ohm) 8
    • Minimum Impedance (Ohm) 3.2
    • Frequency Response (Hz) 35 - 22k
    • Tweeter 1x ø25mm (1 in) rotating on-top titanium dome with neodymium magnet
    • Woofer 2x ø18cm (7 in) crystal woven fibre cone
    • Tweeter Electronic Protection
    • Woofer Chambers 2
    • Bass Reflex Ports 2
    • Magnetically Shielded
    • Crossover Type 2-way
    • Weight (kg) 19
    • Dimensions WxHxD (in) 7.9 x 39.8 x 11.8
    • Dimensions WxHxD (mm) 200 x 1011 x 300
    • Power (Wrms) 100
    • Maximum Power (Watt) 200
    • Sensitivity (dB/2.83V/m) 89
    • Impedance (Ohm) 8
    • Minimum Impedance (Ohm) 3.2
    • Frequency Response (Hz) 45 - 22k
    • Tweeter 1x ø25mm (1 in) rotating on-top titanium dome with neodymium magnet
    • Woofer 1x ø18cm (7 in) crystal woven fibre cone
    • Tweeter Electronic Protection
    • Bass Reflex Ports 2
    • Crossover Type 2-way
    • Gold Plated Binding Post
    • Magnetically Shielded
    • Weight (kg) 7
    • Dimensions WxHxD (in) 21.7 x 8.5 x 6.4
    • Dimensions WxHxD (mm) 550 x 215 x 162
    • Number of subwoofers 4
    • Amplifier Power (Wrms) /unit 120
    • Maximum Power (Watt) 240
    • Frequency Response (Hz) 20 - 350
    • Woofer 1x ø25cm (10 in) downfiring long excursion
    • Auto On/Off
    • Bass Reflex Ports 2
    • Input Level Controller
    • Phase Control Switch
    • Magnetically Shielded
    • Weight (kg) 20
    • Dimensions WxHxD (in) 11 x 18.7 x 18.5
    • Dimensions WxHxD (mm) 280 x 475 x 470
    • Power (Wrms) 100
    • Maximum Power (Watt) 200
    • Sensitivity (dB/2.83V/m) 88
    • Impedance (Ohm) 8
    • Minimum Impedance (Ohm) 6.4
    • Frequency Response (Hz) 45 - 22k
    • Tweeter 2x ø25mm (1 in) silk dome
    • Woofer 1x ø18cm (7 in) crystal woven fibre cone
    • Tweeter Electronic Protection 1
    • Bass Reflex Ports 1
    • Crossover Type 2-way
    • Gold Plated Binding Post / Bi-Wire
    • Magnetically Shielded
    • Weight (kg) 7
    • Dimensions WxHxD (mm) 310 x 310 x 147
    • Dimensions WxHxD (in) 12.2 x 12.2 x 5.8

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