Subsonic noise filtering

When recording a song, your software will record low frequencies as well, frequencies that are, being 20 Hz or lower, beyond the range of human hearing.

That part of the spectrum is not intended to be there in the original recording, it comes as a result of the resonance. Ground shakes and the gramophone rumbles. LP is not perfectly flat and the needle picks up the subsonic sound.






In this tutorial we are gong to see how to remove the unnecessary part of sound that is eating up the file and eating up electricity when sending the low frequency signal to the speakers.

Filtering out the resonance and rumble

To analyze the spectrum we compare the recording of an ordinary song (light green) with recording of a supposed silence (space between songs pictured violet).

Our recording has picked up loud signal around 20 Hz and below.

Supposing there's no instrument playing at 35 Hz, we filter that out.