Acoustic feedback considerations in simulations of sound systems in rooms
Wolfgang Ahnert, Stefan Feistel; Acoustic feedback considerations in simulations of sound systems in rooms. Journal of the Acoustic Society of America 1 October 2016; 140 (4_Supplement): 3128. https://doi.org/10.1121/1.4969794
Abstract:
Computers are employed since about 30 years in the simulation of room- and electro-acoustics. Simulation tools have always considered sources, usually loudspeakers, but not microphones, which is the reason that acoustic feedback has not been considered by any simulation tool yet. As a new feature, a database for microphones is introduced analogous to the database of loudspeakers and other general sources. It is possible in this way to simulate the regeneration of sound over the close system loop, and estimate the maximum gain before feedback, and related influence on maximum sound pressure level and speech intelligibility. The paper briefly describes the important features of the new microphone database. Afterwards, the basic mechanism of acoustic feedback is explained, and the dependence of the feedback threshold of different sound sources and receivers as well as the acoustic properties of the room. By calculating the feedback threshold the headroom of the acoustic gain before feedback may be predicted. These threshold values are calculated by simulation and compared with measurements. This will be done for different loudspeaker-microphone arrangements in a selected conference hall.
