How to interpret a 'noisy' Python FFT?

1. What is FFT noise?
2. How do you read frequencies in FFT?

What is FFT noise?

The "Fast Fourier Transform" (FFT) is an important measurement method in the science of audio and acoustics measurement. It converts a signal into individual spectral components and thereby provides frequency information about the signal.

How do you read frequencies in FFT?

The first bin in the FFT is DC (0 Hz), the second bin is Fs / N , where Fs is the sample rate and N is the size of the FFT. The next bin is 2 * Fs / N . To express this in general terms, the nth bin is n * Fs / N .