FabFilter User Forum
Pro Q3 - dynamics don't work independently with sidechain input?
When Pro Q3 is used as a track or bus compressor the dynamic EQ works independently in each band - but when fed with a sidechain input ALL bands move exactly the same. In other words, there does not appear to be any corresponding band separation applied to the sidechain input.
I had hoped I could use Pro Q3 as a sidechained EQ to duck competing frequencies between two tracks - but I guess that is not possible. Is this a bug or just how it works? If this is by design the sidechain input seems of limited use.
Jeff — Mar 20, 2024
I've also noticed this. And it drove me crazy trying to figure out whether it had to do with my DAWs routing concept. So I just gave up.
This is unfortunate if it's by design.
MB works. But it's not the same.
Hi Jeff,
That's how Pro-Q 3 works. When you are using the internal side-chain the dynamic EQ will be triggered by the band limited signal. When using external side-chain it will be triggered by the complete side-chain signal, not being band limited.
@ Ralph (FabFilter)
I don't mean to be rude (if it comes out that way, I apologize in advance).
But, by "it" you mean to Pro Q3, right?
@ Ralph (FabFilter)
Thank you for confirming but that is disappointing. There are many other Dynamic EQs out there that DO split the sidechain signal by EQ band - the same way the internal sidechain is split.
I guess I don't understand this given Pro Q3's price point. It's a very nice EQ but the sidechain implementation seems incomplete, IMO.
@Valle: Correct, I mean Pro-Q 3. I've adjusted the reply.
@Jeff: There are pros and cons for band passing the external side-chain. We found that most often when using an external side-chain, you don't want it to be band limited to the target frequency. Say you're using the dynamic EQ on a guitar to make way for the vocal in the 3KHz region. You can control this way better when using the complete frequency spectrum of the vocal in the side-chain signal compared to when this vocal would be band filtered around 3KHz.
if you want more control over the side-chain and the frequency domain of the dynamic EQ you can check out Pro-MB. This will give you the option to set the external side-chain to the frequency spectrum of the specific band, or lets you select your own frequency spectrum, both for the internal or external side-chain.
Hi, Ralph!
Is this behavior changed in FabFilter Pro-Q 4?
Hi Valle,
Pro-Q 4 now has the free band, which allows you to select a part of the frequency spectrum to trigger a dynamic band to. This free mode can be applied both to the internal and the external side-chain.
This is by design. When using a sidechain input in Pro-Q 3, all dynamic bands respond uniformly rather than independently. It’s not a bug but a limitation of how the sidechain is implemented. For frequency-specific ducking, a dedicated dynamic EQ with per-band sidechaining (like Soothe or TrackSpacer) might be a better choice.
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