FabFilter User Forum

Spikes in Pro L and how to eliminate them

I had an issue with Pro L and as the forum shows, I wasn't the first one. I worked out how to fix it and maybe it's instructive to others.

When it came to mixdown, Pro L in my master channel let pass some spikes. Evidence was given by the fact that even though the limiter's output was on -1 db and the master's channel on 0 db, the channel's meter showed some ultra short clipping.

When I put Pro C in front, I could see the spikes which looked like transients. Pro C was unable to compress them even with attack on zero. Pro MB did a better work, the clipping got less. But how to avoid it?

I was wondering where these spikes came from. The answer is a bit embarrasing but maybe instructive.

I often use Volcano for adding some filtering to a sound. When doing so, I did not lower the output volume which causes, as I had to learn, digital clipping. How do I know? When I put Pro Q behind, the input level jumps into red. And this is where the spikes come from: digital clipping. When I lower the output level of Volcano (or Saturn or Timeless) while strongly modulating a sound the spikes disappear and Pro L does its job.

I have no idea what sort of signal digital clipping effects but obviously, this sort of signal is neither caught by Pro L nor by Pro C.


Seb Vein

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