## 3aSPb4. An algorithm for generating reverberation as an application of the chaos technique---Return map derived from initial responses.

### Session: Wednesday Morning, December 4

### Time: 8:45

**Author: Tsugumasa Takamiya**

**Location: Acoust. Res. Labs., Yamaha Corp., 10-1 Nakazawa-cho Hamamatsu, 430 Japan**

**Author: Shinji Kishinaga**

**Location: Acoust. Res. Labs., Yamaha Corp., 10-1 Nakazawa-cho Hamamatsu, 430 Japan**

**Author: Fukushi Kawakami**

**Location: Acoust. Res. Labs., Yamaha Corp., 10-1 Nakazawa-cho Hamamatsu, 430 Japan**

**Abstract:**

To synthesize the acoustics of a large enclosure with the aid of a
computer, an algorithm for adding reverberation to the initial response is
proposed. When the initial response is known, the arrival time and the intensity
for each subsequent reflective sound are calculated one after another. After
calculating the time intervals between each succeeding initial reflective sound
and processing them to form a suitable random-number generator, each future
arrival time is then successively determined. From this generator, a return map,
often used in the chaos technique, is adopted. As for the intensity, with the
input value of reverberation time (RT[inf 60]) the decay rate is determined;
from this, the decay rate and the cumulative intensity of the initial
reflective-sound decay curve as a standard are estimated. Then each future
intensity is determined by comparing the cumulative values to the standard. No
awkwardness was heard from the burst tone convoluted with such a calculated
response. Dimensional analysis about the time intervals in the long-time
response calculated by the same algorithm as that used for initial response did
not show that they were from random processes.

ASA 132nd meeting - Hawaii, December 1996