ABSTRACT
The idea of large numbers of loudspeakers around and above the audience in a cinema or home theater is to deliver impressions of specific sounds emerging from specific directions. In loudspeakers, resonances are huge problems because they monotonously color all reproduced sounds. Below about 200 Hz, in spite of some obvious variations related to the very different loudspeaker locations, one can see evidence of relatively independent resonant peaks at clearly identifiable frequencies. Loudspeakers and rooms have been treated as separate entities. As frequency increases it becomes progressively less useful to think about regular patterns of standing waves in rooms. When Sabine introduced the concept of reverberation time into acoustical discussions of rooms at the turn of the last century, he provided both clarification and a problem. The acoustical explanation is the dominance of relatively isolated room modes and associated standing waves at low frequencies, and of a complex collection of overlapping modes and reflected sounds at high frequencies.
