The pitch was about a D or E two octaves above middle C.
There are many instances in which sympathetic vibrations occur. A much lower
vibration can induce a higher vibration which can be heard. One of the explanations
for hearing Leonid meteorites is related to this type of mechanism. For example,
tables have been heard to "hummm" during strong geomagnetic storms - not by
me, but this has been documented as a scientific curiosity. This is also explained
as sympathetic vibration to electrical waves.