Hi all
A bit late but thought that it might help if I gave some examples of the
frequencies being discussed.  The buzz on old a. c. tube-type a.m. radios
many of us grey-hairs remember was the 60 Hertz of the power supply getting
through the ageing components in the power filtering components.  Now that
was quite audible to almost everyone!  Nowadays one can get the same
frequency from some incandescent lights being picked up by some receivers.

Towards the other end of the scale, 15KH, was often heard from vibrating
parts of the flyback transformers of tube type TV sets.  However as I
approached 55 or so, it no longer bothered me.  I understand that the high
frequencies are the commonest ones to be lost from many people's hearing as
one ages.

Thus the 250-300 Hz frequencies would be audible if sufficiently louder than
the ambient noise.  One must ignore the drones and workers of that hyper hive
you just banged!

Hope some of you remember trying to hear the old sets through the a.m. hum!