Research And Implementation Of Acoustic Feedback Suppression In Kara OK Effector

Kara OK effector is a kind of device that can improve the effect of singing. It is common in KTV and ordinary households. The microphone, amplifier, speaker form a basic amplified sound system in these places, where there must be acoustic feedback. Acoustic feedback not only affects the transmission of sound equipment, but also cause howling in severe cases. Then it will make the amplified sound system do not work, hurt ears, or might even burn speaker. Therefore, suppression of acoustic feedback in sound system has become an essential part during sound process.Traditional Kara OK effectors do not have the function of acoustic feedback suppression. Acoustic feedback is only suppressed by designing the building with architectural acoustics principles, which will eliminate frequency resonance point. However, the mobility of the person and goods in the building will lead to an instable and unsustainable acoustic feedback suppression. With the development of science, there are Kara OK effectors with function of acoustic feedback suppression. Effects of acoustic feedback suppression of effector is achieved by the process of signal from microphone. Compared with traditional method, it has a much better suppression effect. However, the current effectors pay much more attention to improving the effect of singing, which makes the function of acoustic feedback suppression not so good. Howling sometimes occurs when singing or speaking. In order to enhance the experience of singing, it is necessary to continue to study the Kara OK acoustic feedback suppression technology to enhance its acoustic feedback suppression performance.Based on the Kara OK effector hardware provided by the cooperation unit and combined specific needs, the research group has completed the research on acoustic feedback suppression algorithm and the designation and the implementation of the system software. The author of this paper is responsible for the research on acoustic feedback suppression algorithms and the implementation of the designed algorithm on DSP. As for the acoustic feedback suppression technology, after comparative analysis, the author choose notch filter howling suppression algorithm as the main research direction. The key to this method is the detection of howling points and the designation of the notch filter. We first detect the frequency where howling points occur using FFT coarse spectrum analysis. Then CZT refined spectrum is used to precisely locate the howling points. Afterwards, the notch filter is used to filter out the howling point in order to achieve acoustic feedback suppression purpose. As for the DSP implementation, it includes the initialization process, the audio data collection and transmission process, acoustic feedback suppression algorithm implementation process and so on. The author also carried out an integrated test on the acoustic feedback suppression performance of the sound effector after the effector system software is completely finished through the efforts of all members of the research group.So far, the author has completed the research of acoustic feedback suppression technology of Kara OK effector and DSP implementation. The effector can well suppress acoustic feedback by test. So the desired goal has been achieved.