Getting FFT result peaks at 0 Hz

Question

I have an audio frame which is a NumPy array of length 16000.

When I apply numpy FFT to the audio frame, I get a spectrum that peaks at 0 Hz. I tried different audio frames from the same audio file but all of them seem to have peaks at 0 Hz.

Could anyone please help me to understand where I am doing wrongly? Thank you.

Answer 1

There is a bias of around -0.2, right? This is a constant value along with the time. This is to say that there is a strong component at 0 Hz compared with the variation around this constant value. You need only to interpret the results.

Solution: try to subtract the average value from the signal in the time domain. I suppose that, magically, the 0 Hz component will disappear.