A new method of curve fiting for calculation of reverberation time from impulse responses with insufficient length


Özgenel Ç. F. , SORGUÇ A.

41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012, New York, United States Of America, 19 - 22 August 2012, vol.11, pp.9066-9070 identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 11
  • City: New York
  • Country: United States Of America
  • Page Numbers: pp.9066-9070
  • Middle East Technical University Affiliated: Yes

Abstract

Most of the room acoustics evaluation parameters are calculated from the energy decay curve obtained from the room impulse response. Schroeder's backwards integration method is one of the most commonly used methods to obtain room impulse response. Although, the method holds its validity since 1964 and used extensively, obtaining room impulse response with sufficient length to observe total energy decay requires high computational cost especially in highly reverberant rooms. In such cases, present acoustical analysis and simulation tools either use data extrapolation and linear fitting methods or they fail to provide any reliable output. Hence, in order to provide reliable data based on such an impulse response, high computational cost and effort are required. In this context, a modification for acoustical analysis methods based on impulse response is proposed, comprising a linear fitting algorithm and extrapolation together with data culling. Proposed method is based on the linear energy decay assumption of Schroeder and ideal energy decay according to global reverberation time estimates. Method is proposed for diffuse field conditions regardless of the length of room impulse response. Validity of the proposed method is checked via a developed room acoustics tool, namely RAT, and case studies conducted with the mentioned tool.