Howling suppression method

Abstract

Abstract PURPOSE:To correct an amplitude characteristic in a transmission function between a speaker and a microphone and to suitably suppress a howling by considering a frequency in which an increasing ratio higher than the average increasing ratio of all spectra is continued as a howling generating frequency and lowering the gain of the frequency. CONSTITUTION:The sound receiving signal of the microphone 10 is converted into the scale of the respective spectra Fi(i = 1-N) by an FFT circuit 11. In a howling detection circuit 12, the increasing ratio from the preceding spectrum of the respective spectra Fi is examined to obtain the average increasing ratio of all the spectra. Then, the increasing ratio of the respective spectra is compared with the average increasing ratio to detect the spectrum in which the average conciderably exceeds a certain level, if the state continues M times, it is decided that the howling is produced in the frequency and an equalizer is automatically adjusted so as to lower the gain in the frequency. Thereby, the change in the transfer function circulating from the speaker to the microphone can be followed and the howling can be suitably suppressed.

Inventors

• 👤 Kazuhisa Tsubaki
• 👤 椿　和久

Bibliographic Details