Cage & Anechoic Chambers -- a few questions

[Eliot Handelman <eliot@xxxxxxxxxxxxxx>]

On the subject of anechoic chambers I have a question. John Cage (in
_Silence_)  tells how he'd been in the Bell Labs a. c.
but found that he heard a low and a high sound, the low sound being due
to blood circulation, and the high sound due to "the nervous system."
(He concluded that there was no such thing as silence, at least from an
perceptual perspective.) I'm terribly curious to know: is this first of
all true. that is, is the explantion correct; are these sounds audible
by anyone; and might the origin of the "nervous system sound" be further
specified?   I've never been in an a.c, though I'd like to: I once
experienced silence in the Montana badlands and I thought it was quite
extraordinary. As it happened I did not hear my nervous system.

 -- eliot

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