Last Updated: 20060803, mei
Thursday, October 5, 9:00 am — 12:00 pm
M1 - LOUDSPEAKERS AND ROOMS
Floyd Toole, Harman International Industries, Inc. - Northridge, CA, USA
Traditional acoustical design methods evolved in large performance spaces such as concert halls. They rely on assumptions that become progressively less valid as rooms get smaller and more acoustically absorptive. In sound reproduction, one cannot consider the loudspeakers and the room independently; they function as a system, differently below and above a transition region around 300 Hz. Above this transition we need to understand our reactions to reflected sounds; below it the modal behavior of the space is the dominant factor. What could be a very difficult situation is greatly alleviated by the ability of humans to adapt to the complexities of reflective rooms, including the abilities to correctly localize sounds in direction and distance and to hear much of the true timbral nature of sound sources. More research is needed before we completely understand the perceptual consequences of acoustical cues in multichannel reproduction as distinct from those contributed by the room. Evidence thus far suggests that, above the transition frequency, the room is a relatively benign and, in some ways, a beneficial factor. There are, however, implications about the acoustical performance of materials in the propagation paths. At low frequencies, room resonances are a major concern, but new techniques allow us to achieve similar and good bass at several listening locations.