Auditioning Speakers

When auditioning speakers, listen primarily for detail without artificial accents. An extra zing and zap may get one's attention on first listen, but it can also get really irritating after many listening hours. It's very difficult to compare speakers from store primer-image-place-holder.jpgto store packed into the demonstration rooms with each other, so reserve the option to return your final choices, or arrange for an in-home audition for your final contestants. As a quick qualifier, rap your knuckles on the speaker cabinet. If it sounds like you are rapping against a piece of granite, this means the cabinet is well damped from vibrating on its own, and will suffer less from coloration due to cabinet resonance. If rapping your knuckles against the cabinet results in a drum-like sound, the cabinet may not be well damped, and could very well obscure sonic detail in the midrange and mid-bass areas. A good cabinet isn't a guarantee of good performance, but it's a start. Click here to listen to a wav file that was recorded when rapping on a speaker that has excellent damping (the speakers shown on the left).

Most speakers have a vinyl finish (usually black) with a wood grained appearance. Some of these look like real wood, and it is difficult to tell that it is vinyl. If you want real wood veneers, many designs offer this as an option. Exotic woods add several hundred dollars to the final cost. Keep in mind that that's money not directly contributing to real performance, even though it may very well make a customer happier with their purchase. The speakers on the left have a rosewood veneer that is exquisite. Other beautiful and unusual woods include jarrah and bubinga.

Move around the room during the speaker demonstration. Listen for how the sound changes as you move side to side, or from a sitting to a standing position. Ambience will be difficult to test in the dealer's demonstration room, since your own room at home will be much different. However, a certain degree of ambience can be heard with different surround systems, such as direct, bipole, and dipole. Careful listening pays off here. You should take a more than a few of your favorite CDs with you to audition equipment. Include music with a wide variety of instruments and dynamics (loudness variations) such as an orchestral symphony, as well as sharp transient sounds (like steel string guitar), piano music, and solo singing voices (especially female). Several brands carry models specifically made for home theater. Keep in mind that it's difficult to tell what's the recording, and what's the speaker, without some reference.

At low volume, even the least expensive speakers can sound very good. Be sure to audition the speakers at the maximum volume you would be listening to them at home. At some loudness point, every speaker begins to produce significant 2003-07-impedence-primer-sinewavewithharmonicdistortion.gifamounts of harmonic distortion. A fundamental sin wave in the low midrange, such as 500 Hz, can have many harmonics that are audible, i.e., 1 kHz, 1.5 kHz, 2 kHz, 2.5 kHz, etc. This makes the sound mushy or sometimes harsh. The diagram on the right shows a sin wave in blue. When there is significant harmonic distortion, the waveform looks like the outline in red (like a square wave). The red area is distortion. So, if the speakers you are considering sound mushy at the loudest volume you like to listen, try a different model or brand. If the speaker doesn't distort at louder levels, it won't "sound" louder than when listening at lower levels, it just will be.

Keep in mind that digital surround is full range in frequency, even in the rear surround channels. So, if you purchase small, limited range speakers, unless you have a good subwoofer, and a proper setup in the receiver or surround processor, you're missing a lot. Also, when using a subwoofer, be sure to calibrate it's level with an SPL meter (Radio Shack analog model set to "C" weighting and slow response) and test tones, usually generated by the receiver, or perhaps a test DVD, such as Ovation Software's Avia test disc, to match the other speakers. For that matter, make sure all speakers are calibrated in relation to each other in terms of level and distance. Otherwise, with a subwoofer, particularly with higher crossover points, not only will the frequency response be unnaturally bass heavy, but the subwoofer will become easy to localize, ruining the illusion of a solid soundscape. If the other channels levels aren't matched, you won't hear the proportion or directional balance that the director or recording engineer intended. A mediocre, well-calibrated system will far outperform a "premium quality" poorly calibrated system.