"Patrick Turner" wrote in message
...




But how does one know how to apply an expander to exactly match
the inverse of the compressor characteristic?
I doubt two wrongs will make a right.

I had a book which described a very simple expander which was just a light
bulb in parallel with the speaker, if I recall. Loud passages would heat
the filament (probably not to incandesence) reduce the load of the bulb and
increase the volume even more. Quiet passages would let the bulb cool, load
the circuit and reduce the volume. It sounds goofy to me, and it's a
circuit which wasn't popular.

There were probably more sophicated expander circuits back then.

A modern sophicated decompressor circuit could match the curve of the
compressor, just as the dolby system does.




Anyhow, in Oz there isn't to much evidence of compression or emphasis of
audio HF on the stations worth listening to; I find the better the
receiver,
the more like FM reception the AM signal becomes.

Patrick Turner.


Here's some of what's been happening in radio audio processing over the
years in the US:

http://www.bext.com/histproc.htm

Frank Dresser