Conference_programme: 18.6 - Acoustics of reverberation chambers
Lecture: Assessment of sound diffusion in rooms for both time and frequency domain by using a decay-cancelled impulse response
Author(s): Hanyu Toshiki, Hoshi Kazuma, Nakakita Tao
Summary:
A method for measuring the random-incidence scattering coefficient of surfaces has been standardized as ISO 17497-1:2004. However, a method for assessing sound diffusivity in rooms has not been standardized yet. The authors have proposed the “degree of time series fluctuation” as an index for evaluating degree of sound field diffusion by using a decay-cancelled impulse response. In this study, we focused on energy fluctuation not only in time domain but also in frequency domain. First, “degree of frequency domain fluctuation” was newly proposed by using power spectrum of the decay-cancelled impulse response. Additionally two indexes which are simpler in a statistical sense were developed. One is a “time series variation coefficient” in energy of the decay-cancelled impulse response and the other is a “frequency variation coefficient” in the power spectrum of the decay-cancelled impulse response. Experiments were conducted using a 1/10 scale model of a rectangular reverberation chamber with various amount of diffusers in order to verify the proposed indexes. As a result, the degree of time series fluctuation and the time series variation coefficient increased when a fluttering echo occurred, and the degree of frequency domain fluctuation and the frequency variation coefficient increased when a low quality reverberation such as a booming occurred.
Corresponding author
Name: Prof Toshiki Hanyu
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Country: Japan
