On Wed, 2011-02-09 at 22:03 +0000, Don Cox wrote:

> I have still not found any clue as to who invented the electronic mixing
> circuit, and when it was first used. Probably very early in broadcasting
> history.

I'm guessing the early 1920s. My memory may be deceiving me, but I could
swear I've seen early radio studios (with the thick drapery and
chandeliers) that had two of the old cylindrical microphones - one on a
stand and the other against the horn area of an internal-horn talking
machine.

NBC did remotes on their very first broadcast in November of 1926, which
means there had to be a way of mixing and muting separate incoming
signals. But if I recall correctly, even that dates back to around 1924
with WEAF, and probably before then.

Michael Shoshani
Chicago