That's awesome, the Optimod has been around for so long, I guess I just didn't realize it, imagine that, half a century!
In a way, that era was the birth of modern processing, using the multi-band technique that doesn't chew up the audio so much. You have the different stages that each do their own thing, made to do one job and do it well, then all combined it makes a nicely processed sound, because all circuits are in their sweet spot. That lowers distortion, especially IMD.
Orban seemed to design his gear for hi-fi, with his musical training, but of course, radio stations being competitive with one another, they had to find various tweaks and ways of hot-rodding their Optimods to sound different than the competition, mainly with extra loudness, which pushed to the extreme will cause distortion again, due to the 'loudness wars'.
Hard to win sometimes.
The other mid-1970s processor to do band splitting was the DAP-310, 3 smooth bands that used an active crossover and FET gain blocks. I had a couple of those long ago, wish I hadn't gotten rid of them.
Boomer
