Beneficial loudspeaker/room/listener interactions

Sound reproduction of the highest quality requires an optimized combination of loudspeakers, rooms and listeners—electroacoustics, acoustics and psychoacoustics. Domestic and monitor loudspeakers have improved because of research investigating the physical sounds arriving at listeners in small rooms and correlating double-blind subjective ratings of sound quality with relevant anechoic measurements on loudspeakers. Loudspeakers designed using specific anechoic measurements and guidance (e.g., ANSI/CTA-2034-B) reliably yield high sound quality ratings in double-blind listening tests in normally reflective domestic rooms. The relative subjective ratings of loudspeakers remain substantially unchanged when comparison listening tests are conducted in rooms with very different acoustics, although the absolute sound quality has changed. Listeners clearly adapt to some of the essential perceptual characteristics of rooms. But there are limits. About 30% of subjective ratings of sound quality is attributable to bass quality. This is different for every arrangement of loudspeakers and listeners in every different room. Seat-to-seat variations at low frequencies are large. Absorption is traditionally used to damp bass resonances. However, for reproduced sound, multiple subwoofers, with or without signal processing, can manipulate room resonances. These schemes, with equalization, can substantially attenuate audible resonances while yielding much reduced seat-to-seat variation, using no passive acoustical devices.