Microphone protected against acoustic feedback

摘要

If microphones are used for direct sound amplification, the problem of acoustic feedback almost always occurs. This manifests itself in a loud whistle. Echoes after loud tones are also attributable to this. Filtering out this whistling tone simultaneously also suppresses the tone which is to be amplified. In most cases, however, the acoustic feedback then occurs at a different frequency. There is then only one possibility, which is to reduce the sensitivity of the microphone. The singer or speaker must then sing or speak very loudly into the microphone directly in front of his mouth. Naturally, this leads to changes in the sound pattern. The invention deals with the design of a microphone which suppresses acoustic feedback by electric means. This makes it possible to speak into the microphone from a distance of 10-50 cm without acoustic feedback occurring even with a high volume of the loudspeaker. Nor does the microphone need to exhibit an extreme directional effect, which is highly desirable for natural reproduction.