Enough Room? Page 3

Avoid placing large pieces of furniture between the loudspeakers (between loudspeakers, the best furniture is no furniture). Imaging will usually suffer, otherwise. You might be able to get away with this if the loudspeakers are well out into the room and the credenza or whatever is back against the wall; I have on occasion used this arrangement with effective results. Similarly, a large coffee table in front of the listening location, with the attendant reflections off of it, is also usually a no-no.

And don't forget that where you place yourself will have a substantial effect on the sound. Position your listening chair, if possible, well clear of the rear wall; that will often (but not always) improve soundstaging and low-end smoothness, though sometimes at the expense of low-end weight. If domestic considerations require that the furniture be flush against the wall, a solution I have found to be satisfactory is to have a light, movable chair---a director's chair, perhaps, which I can easily maneuver in front of the wall-mounted furniture arrangement for use when I want to listen critically.

In my opinion, listeners often sit too far from their loudspeakers. The farther away you sit, the more the room itself affects the sound you hear, particularly at mid- and high frequencies. Yet sitting too close can also present problems: the ideal listening position---the "sweet spot"---is smaller, and if you sit too close, the outputs of the individual drivers in the system may not blend properly. The answer, again, is being open-minded enough to experiment. Don't automatically sit 15' away because that seems the most logical location with your normal furniture arrangement, or because that position worked best with your last pair of loudspeakers, or in your previous listening room, or simply because "you always have."

Furthermore, the height at which you listen is very important. With a stand-mounted loudspeaker, that means trying different stand heights before making a final choice. You might even find that the height recommended by the manufacturer, or their "dedicated" stand itself, is not always optimum for your personal listening situation. Getting the tweeter at or slightly above ear height, for a seated listener, is usually best. But not always. Experiment.

A number of manufacturers are now in the business of selling room-treatment products of various types to help optimize room acoustics. The most widely used are damping panels placed on the walls of the listening room. These range from shaped acoustic foam (available from Sonex, Audio Advisor, Audio Express, and Audio Concepts, among others) to decorative hangings and free-standing panels usually made of rigid fiberglass in a fabric-covered frame. The latter are not that easy to come by commercially (Monster Cable used to market them, but has not been promoting them recently), but the resourceful do-it-yourselfer could build them without a great deal of difficulty. Rigid fiberglass sheets of varying thickness are available from most insulation suppliers. Or you could use fiberglass of the flexible, attic-insulation variety. But be careful---avoid skin contact with the raw fiberglass (it's nasty, itchy stuff), and try not to shake fiberglass dust into the air (footnote 3). The most difficult part of the project will be framing and covering the fiberglass. I strongly recommend a fabric cover of some sort over it, for both cosmetic and health reasons.

Beyond this, the products tend to get more specialized and more expensive. Tube Traps are by now known to most audiophiles. They are designed primarily to reduce low-frequency pressure buildup in the room corners, where such frequencies are known to get together and party, disturbing the acoustic peace of the rest of the room. Traps are also often used against wall surfaces as well. JGH and LA reviewed them way back in Vol.9 No.3. A more recent variation on this idea is the Phantom Acoustics Shadow, which RH reviewed in Vol.12 No.12; it takes an active approach to reducing pressure buildup in the corners.

Also new are the products from RoomTune. Their line consists of small, freestanding panel absorbers and smaller devices designed to fit into the upper room corners and high on the walls near the ceiling. Some of this company's ideas on room acoustics are decidedly unconventional. GL is currently living with their products, and will report his findings in a future issue. Stay, ah, tuned.

Then there are RPG Diffusors and related products. These operate on the principle of establishing a smooth, controlled diffusion of sound (though they also make a device called an Abffusor, which combines diffusion and absorption). These are perhaps the most expensive of the room-treatment devices, and while mainly designed for recording studios, they have found their way into some home listening rooms. Keith Yates commented on them for Stereophile in Vol.11 No.4.

Many of these products, and others which pop up from time to time, are effective, but I strongly recommend working to obtain the best results you can with normal domestic furnishings before resorting to them. Again, try various furniture arrangements and loudspeaker (and listener) locations first, remembering to do something about those flat, reflective walls to improve both their dispersion and their absorption in the appropriate places. Then, if the results continue to defeat your best efforts, you might look into specialized room treatments. If you need such dedicated products, and they are acceptable to the budget- and decor-meister in the family, they should be your final room tweak, not your first.

Footnote 3: We're not talking asbestos-type problems here, but inhalation of brittle, non-degradable fibers is unlikely to help promote rosy cheeks. Nor is getting them in your eyes a good idea. Which are two reasons why I have reservations about recommendations to use this material to reduce the noise of an air-conditioning system by lining the inside of the ducts with it.
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