In message , Blair Maynard
writes

snip

It is obvious that people talk over each other, so either they are all in
the same room, or they have a full duplex system. Actually, it sounded like
they all had open mics. We don't hear much in the way of non-vocal noises
other than the machinegun bursts. Presumably that burst was picked up by a
mic which was open although nobody was speaking, so there had to be at least
one open mic, since they didn't have voice-activated mics back then.

Some of these things may be explicable. We would need to know the location
and recording characteristics of the recording device and how it was hooked
up to the comm system of the aircraft.

Basically all headphones are in parallel, aren't they? My recorder was
across my headphone feed and I got all the intercom chat.

Mike
--
M.J.Powell