Not necessarily. A lot of analog front ends have a highpass filter around 8-20 Hz (the audible threshold). I don't really know why, it might be to prevent DC dr

Not necessarily. A lot of analog front ends have a highpass filter around 8-20 Hz (the audible threshold). I don't really know why, it might be to prevent DC drift so that there is no asymmetrical distortion in the signal fed to the ADC, just speculating. But I do know a lot of systems just won't capture <20Hz.