Dan_UK wrote:Could the changing levels be because the Mercury & Cambells were on 4 or 5 minute discs and the levels would change from disc to disc? They'd have to have 2 (or more) disc cutters operating so that one could start recording just before the other one reaches the end so there'd be a small overlap, and the levels on each one wouldn't necessarily be the same.
That's part of it: the bit of repeated dialogue might be at double the volume going from the end of one side to the beginning of the next. But beyond that within a disc side there can be big volume differences, in Welles' narration, in the same two characters conversing, whatever. I'm not talking about a spike because somebody yelled, I mean stretches of time. So, the vagaries of 1939 audio technology and why AM radio used heavy compression, I guess.