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Tips to Combat Loudspeaker & System Brightness

by August 29, 2004

You researched and went out shopping on the internet and/or retail stores to assemble the ultimate home theater system. You spent hours auditioning all the competing brands, assuring yourself you bought the best system for your hard-earned money. You anxiously run home to connect your newfound system, drooling in anticipation like Pavlov's dog for you're first listening experience.

Everything sounds as good or better than you envisioned. You fall in love with your system and pride yourself on showing it off to your friends/family at every opportunity you get.

A few months pass and gradually your viewpoint of your dream system changes. You begin noticing that when listening to two-channel audio, some of your CD's sound excessively bright.

How could this be, and why didn't I notice this before you ask yourself? Did I buy the wrong Speakers, Amp, CD player, etc?

Relax and don't box up your equipment just yet. Listed below are some common possibilities, which may attribute to system brightness.

Let me provide the simplest answer first which may address about 80% of these occurrences.

Many CD's suffer from excessive brightness for the following reasons:

  • Recorded from original analog source thus loss of resolution is realized.
  • Poor mix at recording studio by the sound engineers. There are many cases where recording engineers Over-EQ the recording to compensate for original limitations of the source.
  • Many CD's are mixed with too much EQ as they are geared for the average consumer's system, that when played back on a high fidelity system they sound overly bright.
  • Hyper-compression and digital clipping in recordings

For more information on source issues, check out our Audio Formats & Compression Articles

Bottom Line: A simple test to determine if your systems hardware is the culprit of excessive brightness is to play a large sample of CD's you are accustomed too. If all of them sound bright, than it may be hardware related. If some sound bright, but others don't, it may be attributed to the reasoning above. Usually CD's recorded "DDD" are better quality than "ADD" or "AAD" because they are mastered directly from a digital source.

For the remaining 20% of occurrences of system brightness not attributed to the source, the following are possible:

Placement of speakers in a lively room

  • Speakers placed in a room containing a lot of glass, mirrors, and tiled floors tends to overly emphasis and reinforce high frequencies as they continuously bounce off these reflective surfaces.
  • Placing a pair of speakers between a large TV tube may have the tendency of causing the speakers to sound too bright as the high frequencies bouncing off the walls reflect back at you from the glass picture tube. In home theater applications, this is almost impossible to avoid, but it should at least be noted.

    Note: Placing pictures on the walls or adding carpeting to the floor can help tone down the room and thus reduce system brightness.

Speaker Toe-in

  • Many speakers are designed to exhibit optimal performance 30 degrees off axis and may sound excessively bright if toed into the listening position.

I recommend experimenting with speaker positioning within the room to achieve desired results.

Further Recommendations to Tame Brightness

Room acoustics play a vital role in determining system fidelity. We suggest reading up on articles in our Dedicated Acoustics Section for more details.

Some esoteric dealers and or cable companies may suggest experimentation with different brands of speaker cables. As a minimum, you should always use 12 AWG speaker wire to minimize "I^2*R" losses and to reduce DCR characteristics of cabling. However, excessive cable reactance for long runs can affect sound quality as well due to the impedance vs frequency relationships. It is difficult to find these specifications as many manufacturers give very little metrics on their products. If you cannot measure the properties of cables, we suggest at least assuring the cables you are considering don't fall under our Top Ten Signs a Cable Vendor is Selling You Snake Oil criteria. It is also recommended that the reader peruse our Cable Information Section of Audioholics for more information on this topic.

If you have exhausted all permutations of {room placement for your speakers, different cabling, etc}, with no sonic improvements and cannot place your system in a different room, than I recommend the following:

If you purchased speakers with horns, or metal domes, try auditioning other brands with silk or cloth dome tweeters within your budget in your home listening environment.

System brightness solved?

Yes. Good, now bring back your old speakers in favor of the new ones.

No. Ok, keep which ever speakers you liked best and move on to auditioning different Receivers.

Did the new Receiver help tame brightness?

Yes. Good, now bring back your old Receiver in favor of the new one.

No. Than the best recommendation I can make is to use your tone controls. As much as I do not like using tone controls, there are cases where they may help suit your listening tastes.

Listed below are several reasons why I reserve using tone controls as a last option:

Many receivers' tone adjustments are done through the analog domain, adding additional circuitry in the critical analog paths, which results in audible signal quality degradation and/or compression.

Using a tone control is not specific at reducing a particular problem frequency. Many tone controls labeled "treble" roll of broadband frequencies centered at 10KHz and thus reduce frequencies that are not attributing to system brightness resulting in unwanted loss of fidelity.

Note: One can argue that using an equalizer is a better option as you have more control over what frequencies are being boosted or attenuated. This is true; however, adding an EQ into the preamp section of your Receiver may throw off the calibration of your Dolby Prologic/Digital controller and may also overload the DSP chip causing damage or unwanted clipping.

Note: Use equalizers with caution and only use them in two-channel mode if at all!

last updated 08/08/05

 

About the author:
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Gene manages this organization, establishes relations with manufacturers and keeps Audioholics a well oiled machine. His goal is to educate about home theater and develop more standards in the industry to eliminate consumer confusion clouded by industry snake oil.

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