Technology: Speaker Setup

What you want (and me too) is for you to enjoy your speakers performing at their very best. I'd like to suggest some simple guidelines that will help you attain this goal. My intention is not to give a short course in physics, but rather I want to provide you with some powerful guidelines that work and are easy to implement. Our speakers are "line-source dipoles" by nature (energy emanates equally from both the front and the back of the speakers with little vertical dispersion). Set up procedures differ somewhat from those of traditional speakers.
     The room (acoustical environment) in which loudspeakers are listened to must be viewed as a major acoustical component of your system. The speaker's position relative to the listener's position is a critical variable which can be optimized for virtually any room. To do this scientifically requires sophisticated equipment and a working knowledge of physical acoustics and psycho-acoustics. Fortunately, with a little guidance the human auditory system (which is more capable than any man-made technology is judging "good" sound) can optimize a sound system with incredible accuracy. Let's consider some basics.

1. Room Considerations:

Acoustically, a room is an enclosure that can significantly alter the sound coming from speakers. Sound waves reflect from walls, floor, ceiling and objects within a room and can result in audible wave-interference patterns. To a lesser degree, diffraction and refraction can also alter the sound. Our objective is to reduce undesirable room effects to a minimum.

2. Room Treatment:

I speak in generalities because not all rooms have similar characteristics and some even seem to openly defy attempts to "tame" them. With respect to the latter situation, a militant mentality helps. Fortunately, most room problems surrender to the application of some simple rules-of-thumb.
     Depending on the dimensions, shape and surface reflectivity, a room can create a series of effects, some desirable (as in the case of rich music-hall acoustics) and some undesirable (comb-filter effects, standing waves, slap-echo, etc.). To win the war, one must know the enemy. Our adversary is the accumulation of too much reverberant energy in the room. We are mainly interested in hearing the direct sound wave and not so much its past history. Although, total absence of reverberant energy can make sound too dry, too much creates the adversary. Therefore, our task is to control the many manifestations of reverberant energy, not necessarily to totally annihilate them.

3. Optimum Room Treatment:

If it is within the scope of an installation, my preference is making the listening end of the room reflective and dispersive, and the speaker end of the room absorptive. This scheme requires that the listening end of the room be both reflective and dispersive. That is, the wall behind the listeners and the side walls down to the beginning of the of the absorption treatment consist of dispersing elements such as the RPG devices.
     The absorptive end of the room should be treated both on the back and side walls. The side walls should be treated slightly beyond the speakers to eliminate direct wall splash. This can also be accomplished by a less expensive "do-it-yourself" approach if budget is a consideration. I'll briefly elaborate on this.
     An inexpensive but very effective "dispersing" wall can be made by mounting 4' by 8' sheets of plywood on the reflective portion of the room walls. However, instead of placing them flat, the center (along the 8' vertical dimension of each sheet) is lifted away from the wall about 4" while keeping the edges against the wall. This is accomplished by cutting each sheet in half, along the 8' dimension. An edge-mounted "2x4" stud is secured vertically on the wall, centered directly under the cut. This raises the center of the sheet from the wall, and creates a "serpentine" effect from the top view. The thicker the panel the better. I recommend 3/4" sheets with the exposed side finished. The vertical junctions can be mitered for a fine fit, or trim strips can be used to dress up the seams. For a more sophisticated application, make the vertical cuts randomly instead of at the center of each sheet. This results in a more random reflective field, making reflections less frequency specific. For those who really want to get involved, the raise seam on adjacent sheets can be altered from vertical to horizontal and so on. This randomizes vertical components of reflective energy as well as horizontal components.
     The "dead" end of the room can be economically treated by edge-mounting studs vertically along the walls of the absorptive portion of the room. I recommend "2x6" studs, fastening them directly to the underlying wall studs with countersunk lag bolts. Insert loosely-packed fiber glass wool between studs from floor to ceiling. Then, cover the wall with an audio-grade grille cloth. Contact me if you need further explanation. With commonly available materials and a little effort an average-sized room can be treated for several hundred dollars rather than several thousand dollars if commercially available components are used.
     If room aesthetics won't allow a full-blown "live-end, dead-end" installation, a partial installation is better than nothing. For hard-core cases in which aesthetics totally dominate, we have developed a device (SALLIE) that does a great job of controlling the potentially troublesome back-wave energy that emanates from any dipole speaker. SALLIE is quite effective and "she" hides behind the speaker so as not to disrupt the room decor. Get acquainted with SALLIE on our accessories page.

4. Final Tips:

Now that the acoustical properties of your room are properly controlled, speaker and listener positions need to be considered.

a. Dipole speakers like breathing room behind them. Use as much space as you can afford. If the speakers must be placed directly against the back wall (the worst possible condition for a dipole device) life doesn't end. Simply toe-in the speakers to reduce direct reflections from the back wall. The toe-in angle can be large, on the order of 30 to 40 degrees, since Sound Lab speakers have wide, non-frequency dependent, sound dispersion angles. Use as large an angle as necessary.

b. Room modes "generally" cause a low-frequency "suck-out" in the geometric center of the room. This is "generally" no the best place to put your couch. I say generally because some rooms like to make me appear incompetent by not following my rules-of-thumb. Just use this advice as a starting point.

c. Low-frequency energy seems to socialize near walls. Therefore, if you wish to increase bass frequency energy, put your couch near a wall. By judiciously placing the couch, you can get the best spectral balance that pleases you the most.

d. Side-wall placing is not particularly critical with our speakers. This is because an energy null exists at the sides of the speakers and little energy reaches the side walls. The exception is low-frequency energy, which goes everywhere with careless abandon. Acoustical devices to control "lows" must be huge to really effective, since the wavelengths are so long. From long, hard experience in trying to induce bass energy to go where I want it I have found it less frustrating to go where it is camping by moving either the couch or the speakers (or both in some cases).

e. As a starting point, set the speakers about 3 feet from the back wall and toe them in such that if imaginary perpendicular lines were to extend from the center of each speaker, they would cross at your head position as you sit at your favorite listening spot. Initially, place your couch about 12 to 16 feet from the speakers. Separate the speakers approximately 8 feet apart, center-to-center. The closer you sit to the speakers, room influence on the sound is less. Sound Lab speakers have an intentional uncanny property that they don't seem to get louder as you get closer to them (a characteristic of the line source). Thus, you can sit right up next to them without penalty. From this starting point you can make adjustments as your intuition guides you. If you get confused as you alter speaker and listening positions, you can always default to the starting point as a reference and start over. We have casters available to make it easy to move the speakers.

Conclusion:

Armed with these guidelines, you should be able to easily home-in on an acceptable arrangement of speaker and listening positions. We have found that because of the large acoustic radiating area and the wide non-frequency-dependent sound dispersion of our speakers, set up requirements are not terribly rigid.
     More than likely, the first position in which you place the speakers after uncrating them will sound acceptable. If all else fails, call us and we will be more than pleased to assist you.