It is easy to see that feedback is a very artificial sound.  Its waveform is almost a perfect high frequency sinusoid in a low frequency sinusoidal envelope.   This does not look at all like speech or a musical instrument. The wave is too simple.    

Looking at the Spectrogram yields more information about the nature of feedback.  It shows a very pronounced root frequency as well as the harmonic overtones of that frequency. 

The frequency domain representation sheds even more light on the subject of feedback.  Its basic structure has very high power narrow band peaks.   They are very concentrated signals that occur at a very limited number of frequencies.  Thus if we can figure out how to find these specific frequencies we should be able to eliminate the without too much trouble.

---

Home           Back to Feedback