FabFilter User Forum
Pro-C 3 "mix" slider is just a duplicate ratio control?
The "mix" parameter sounded very off to me, so I verified the behaviour using DDMF Plugin Doctor, and the transfer function is indeed equivalent to a ratio adjustment, with values over 100% achieving a negative ratio. So, why?
I appreciate the ability to use negative ratios for ducking, but there was already a ratio control. Could you not simply have added this feature to the existing ratio knob instead of making a duplicate, redundant parameter? And please add a real mix knob while you're at it, because using the individual dry and wet level knobs is annoying when trying to dial in parallel compression on a single track :]
Other than that, great work! Congrats on the big update!
Nikita Andreev — Jan 17, 2026
Here is a screenshot showing that an 8:1 ratio with 50% mix is equivalent to a 1.8:1 ratio with 100% mix:
postimg.cc/p9ZsWqsc
Here is a screenshot showing what the transfer function is expected to look like for real parallel compression:
postimg.cc/VSRKfDKH
it's the same as in proC2 :)
you can do traditional parallel comp by using the "dry output" control
Huh, yeah it seems I overlooked that feature in C2!
It is still very strange to have it called "mix" instead of ratio, and even stranger to have it hidden away in the output section instead of on the actual mix knob, in my opinion as a user
Hi Nikita,
The Mix slider scales the resulting, smoothed gain change. Note that this gives quite a similar but not exactly the same effect as just changing the Ratio. It might give a similar transfer curve plot, but that can't properly show the effect of attack/release.
So, setting mix to 0% will scale the gain change to zero, hence leaving you with the dry signal. The advantage of scaling the overall gain change instead of just mixing dry/wet signals, is that Mix can easily also go to > 100% values.
Maybe renaming "mix" to "intensity" would be more intuitive, so one doesn't use mix but instead dry/wet when going for traditional parallel compression