I have had it with commercials on cable TV being a lot louder than the program I happen to be watching. I have also had the reverse where the program switches scenes and you cannot make out what the whispering actress is saying.
I know products are already on the market that take care of this problem, but I thought it would be fun to fix it myself. I come from the microprocessor/digital side of things so I really have not played with audio a whole lot.
I current use RCA audio cables between my cable box and sound system. I would like to plug my device between those two devices so that my amplifier receives the modified normalized audio signal.
So far I have been looking at Automatic Gain Control circuits as a solution. Is this the right way to go or should I be looking at something else?
If possible, please include links to schematics, components, etc with your post. Thank you in advance for your help.
Best Answer
Typical electroacoustic systems use compressors (and variants - limiters and levelers) for exactly that - controlling the dynamic range of the signal. Those devices are used in audio production, by musicians, or e.g. to limit the modulation depth of a radio transmitter. Analogue compressors are still in wide use (I'd even say analogue compressors are more common in professional recording studios, not to mention vacuum tube ones).
What you need is basically a limiter or leveler, googling around for 'audio limiter schematics' yields a lot of results, I'd start the research from there. E.g. this one looks reasonably simple. There are also many circuits like this one, based on NE577 or NE572 or similar compander chips.
I hope that helps!