Re: An un-recordable sound?

["Scott Fraser" scottbfraser]

<<Low frequency sounds seem to be easier to record than for me to hear -
I once recorded a dawn chorus at Aldringham heath, which is about two
miles from Sizewell nuclear power station in Suffolk (UK). I use a
MKH30/40 and threw out the whole recording on playback as it was
polluted by hum and some harmonics. I never heard this in the field,
and on going back there try as I might I could not hear the hum. I can
hear it if I go much closer to the power station on the beach path.>>

Being near a power generating facility perhaps the hum was induced
electromagnetically into the recording gear & was not an acoustic event.

Scott Fraser