Speaker Placement
Although your AVALON ACOUSTICS loudspeakers may be placed in a wide variety of positions relative to the walls of the room, it is still wise to experiment a bit to achieve optimal results. The suggested minimum distances for the ISIS are 3 feet from one wall (side or rear), and 5 feet from the other (all distances are measured to the center of the woofer cone). This will provide the proper degree of bass reinforcement, as well as minimize early reflections.
There is no suggested upper limit for the distances to the walls. Even a distance of 10 feet to one wall and 15 feet to the other wall will provide suitable bass reinforcement, and problems due to early reflections will be non-existent. However, regardless of the absolute numbers used, the most even bass response will be attained if the distances from the side wall and the rear wall are not overly similar.
Early Reflections
When arranging the furnishings in your listening room, remember that reflective objects should not be within a five foot radius of either the speaker or listener to avoid early reflections. This suggests the possibility of a dual-purpose room, with one end devoted to music reproduction, and the other end for another use, such as a study or office. In this way, the area behind the listener will contain items that will reduce problems with standing waves and/or flutter echo, while the zone around the speakers remains relatively free from reflective objects.
If you wish to achieve an even more spacious sound-stage, it may be useful to place a sonically absorbent material on the side and rear walls near the speakers. This can be particularly effective at the points where the sound wave is directly reflected to the listening position (a mirror can be used to determine these points, as illustrated in Fig. 8.2). As the distance to the wall becomes smaller, the suppression of these reflections becomes more important.
Early reflections will tend to diminish the soundstage in the direction of the reflections, i.e. early reflections from the side walls tend to reduce sound-stage width, while early reflections from the back wall will reduce image depth. We have found that a strong sense of depth enhances the feeling of involvement when listening, due to the three-dimensional solidity of images. Therefore, it is more important to have a greater distance from the speakers to the rear wall than to the sides walls. Typically, this is easier to achieve if the speakers are placed along the short wall of the listening room.