Abstract
It is often argued that the interference of sound from distant loudspeakers is negligible in the case of band-limited noise. Simple theory and experiment in a reflection-free environment with a pair of loudspeakers radiating a third-octave noise proves that in the case of coherent supply SPL variations are considerable. The variations disappear when non-coherent signal is applied indicating that non-coherent supply of loudspeakers is necessary wherever approximation of diffuse sound field is required.References
[1] ISO 4869-1: 1990 Acoustics — Hearing protectors, part 1: Subjective method for the measurement of sound attenuation.
[2] ISO/DP 8253-2: 1987 Acoustics — Audiometric test methods, Part 2: Sound field audiometry with pure tones and narrow-band test signals.
[3] A. LIPOWCZAN, CIOP Seminar on implementation of the stand for certification of hearing protectors, Warszawa, January 1992.
[4] J.S. BENDAT, A.G. PIERSOL, Random data, Analysis and measurement procedures, (in Polish), PWN, Warszawa 1976, p. 110.
[5] K.D. JACOB, T.K. BIRKLE, Prediction of the full-space directivity characteristics of loudspeaker arrays. Audio Eng. Soc., 38, 4, pp. 250259, (1990).
[2] ISO/DP 8253-2: 1987 Acoustics — Audiometric test methods, Part 2: Sound field audiometry with pure tones and narrow-band test signals.
[3] A. LIPOWCZAN, CIOP Seminar on implementation of the stand for certification of hearing protectors, Warszawa, January 1992.
[4] J.S. BENDAT, A.G. PIERSOL, Random data, Analysis and measurement procedures, (in Polish), PWN, Warszawa 1976, p. 110.
[5] K.D. JACOB, T.K. BIRKLE, Prediction of the full-space directivity characteristics of loudspeaker arrays. Audio Eng. Soc., 38, 4, pp. 250259, (1990).
