Total posts : 45366
I’ve wondered which would be better, loudness versus quality, between symmetrical and asymmetrical to +125 percent. My personal feeling is that phase scrambled audio at +/- 100% is the safest thing to use.
There are different schools of thought, some are concerned about radios distorting at high levels of negative modulation because of cheap detectors in them. Some of the more recent vintage transmitters don’t even like modulation past 90-95% negative. I think the problem is pretty much solved now, but we have a few decades worth of AM broadcast transmitters at stations that should watch negative peaks.
That could have been one of the things that led to using more asymmetrical mod, to keep audio up by going more positive.
Then too, if you’ll even hear the added volume would depend on how much you compress, limit and clip already. I’d think if you were broadcasting natural dynamics, you probably won’t notice the difference between peaks going to 100 or +125, but extra db on brick wall audio should be heard.
The only problem then is that so many peaks being treated to the asymmetrical processing, the distortion would probably be Super Bad!
There must have been some studies on this, at around 1970 when the FCC was considering the ‘limiting’ of positive modulation. Apparently before then, there was no ‘limit’ on the positive peak modulation, so stations mightt have been doing something to trigger the FCC on it?
Modern CBers are really into asymmetrical mod these days, the guys who talk on the nationwide channels. 300% mod is not untalked about, and they’re building 12-pill wide dynamic range superamps for CB. You should see the sine waves on their scopes, with big troughs on the negative peaks, “Look at that signal, you’ll see the carrier is never cut off!”