Common misconception... Very high frequency audio
does not equal
electromagnetic radiation (radio, etc.). Audio is the compression and
expansion of air, so it isn't really affected by EMI.
Ok, but the microphone converts the air vibrations into electric
vibrations. People have picked up radio in their braces and fillings.
It doesn't seem entirely unreasonable to guess that an electromagnetic
radiation signal vibrating at the same rate as some of the electric
signals in the cables and sampling device might cause audible interference
in the result.