The main aim of room acoustics is to predict reverberant properties of enclosures from measured or numerically simulated room responses. In this paper, this issue was examined in low-frequency range where acoustic characteristics of rooms are strongly frequency dependent due to differences in a modal damping. A theoretical description of a decaying sound field was based on a modal expansion of the sound pressure, and a reverberant response of the room was initiated by emission of Dirac delta time impulse or by switching off a time-harmonic source. Theoretical findings were employed to determine reverberant characteristics of a coupled-room system containing two connected rectangular subrooms. Simulation results have shown that a sound decay after steady-state harmonic excitation is strongly influenced by the sound frequency and due to large fluctuations in a decaying pressure; numerical techniques for smoothing decay curves are needed. Calculations also revealed that in some one-third octave bands, the decay function found via backward integration of squared room impulse response (RIR) changes very irregularly impeding a proper qualifying of nature of sound decay.
Theoretical and Numerical Determination of Low-Frequency Reverberant Characteristics of Coupled Rooms
Contributed by the Noise Control and Acoustics Division of ASME for publication in the JOURNAL OF VIBRATION AND ACOUSTICS. Manuscript received August 6, 2014; final manuscript received February 18, 2015; published online April 15, 2015. Assoc. Editor: Theodore Farabee.
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Meissner, M. (August 1, 2015). "Theoretical and Numerical Determination of Low-Frequency Reverberant Characteristics of Coupled Rooms." ASME. J. Vib. Acoust. August 2015; 137(4): 041013. https://doi.org/10.1115/1.4029991
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