Barry_Green
Moderator
Looks like noise reduction and high gain. The AC90 doesn't really get "noisy" at all, but it does get smushier at higher gain levels. It can go very high in gain without any appreciable increase in noise, and as far as I can tell that's because a commensurate amount of noise reduction is employed to counteract the higher gain.
Keep it at zero gain and it's infinitely better.
Keep it at zero gain and it's infinitely better.