## 4aAA5. Analysis and synthesis of room reverberation in the time and frequency domains---Application to the restoration of room impulse responses corrupted by measurement noise.

### Session: Thursday Morning, May 16

### Time: 10:10

**Author: Jean-Marc Jot**

**Author: Guillaume Vandernoot**

**Author: Olivier Warusfel**

**Location: IRCAM, 1 Pl. Stravinsky, 75004 Paris, France**

**Abstract:**

This paper reviews a statistical time-frequency model of the late diffuse
reverberation in rooms. In this model, the later part of a room impulse response
is described by a ``time-frequency envelope,'' defined as the ensemble average
of the time-frequency energy distribution in the late decay. The time-frequency
envelope is independent of the source and receiver locations and is
characterized by two functions of frequency: the reverberation time and a power
spectral density called the ``initial spectrum,'' which corresponds to the
product of the diffuse-field transfer functions of the source and the receiver.
An analysis method is described for deriving these parameters from a measured
impulse response, yielding an accurate estimate of the reverberation time with
arbitrary resolution in the frequency domain. The time-frequency envelope
defines a time-dependent filter which transforms a sampled stationary Gaussian
white noise into a synthetic model of the late reverberation decay. Substituting
this synthetic reverberation decay to the part of an impulse response that is
corrupted by measured noise, yields a restored impulse response allowing
faithful auralization by convolution with anechoic source signals. The models
and the methods described are illustrated on impulse responses measured in a
concert hall.

from ASA 131st Meeting, Indianapolis, May 1996