I have a noisy audio file, available here (It is safe to download if you wish to) https://ufile.io/pstrt
Now I need to filter this signal to remove the noise. However, I have no idea what is causing the noise in the first place. Perhaps it is obvious even from the two figures I have shown but unfortunately not for me. I could play a guessing game and apply different configurations of lowpass, highpass and bandpass filters, but I have quite a few of such audio files to analyse. Thank you for any help.