Detektion und Unterdruckung von Rückkopplungen in Lautsprecher-Mikrofon Anordnungen

Diploma Thesis (1.175 KB)

This work shows how howling frequencies in loudspeaker microphone setups can be suppressed. Besides traditional stabilization methods for electroacoustic loops such as frequency shifters or pitch shifters, methods for detecting and suppressing howling using notch filter techniques are demonstrated. The different detection methods are tested and compared to each other concerning their detection speed and efficiency. Furthermore the design of a fixed and adaptive filter bank and its filter tracking is sketched. The integration in a total system allows efficient howling suppression and an increase of the maximum gain of the loudspeaker microphone setup. The presented system is a real-time implementation programmed in Pure Data. In conclusion, the entire implemented system is tested and evaluated.