Re: two phones are placed with the mouth pieces to the ear pieces

You would hear the word 'hello' said over and over again.  I could
not time the rate exactly.  It seemed like about 3 'hello's per
second.  Very quickly the ordinary feedback of noise from the
connected phones drowns out the repeat of the hello's.  If it were
not for the feedback of noise which interferes with the 'hello's then
you would hear 'hello' repeated over and over again indefinitely.
I heard at least 6 'hello's in my experiment before the feedback
noise drowned it out.

Kermit