FabFilter User Forum
Weird issue with FabFilter Pro-Q 4 on Cubase 13
Hi everyone,
I recently bought FabFilters' Pro-Q 4 (not having owned Q 3 previously, this is my first FabFilter plug-in), and noticed one issue that I did not manage to fix until now; Whenever I use it on a mono channel, Pro-Q 4 appears to be somehow "duplicating" the output. I tested this by slotting another plugin behind the Q 4, which consistently showed me the input of that plugin to be 6 dB higher than the output of the Q 4. Also, it appers to only be filtering one of those audio streams. When I take a high-cut filter and do a sweep of the frequencies it will sound as if one of two identical signals is filtered, while another one remains untouched, not to mention that the RTA of the plug-in after it will still show frequencies that should have been cut.
I'm trying to find out whether this is user error from my side or an actual bug. Note that this only occurs when the plug-in is slotted into a mono-configured channel, stereo channels work fine.
To me this sounds like the signal may also be somehow routed "around" the plugin and then added back to it after, but that's not a feature that I'm aware of in Cubase...
Did any of you run into the same problem?
Could it be you are using the VST2 version of Pro-Q 4 on a mono track in Cubase? There is an issue with the audio routing with the mono VST2 version, where the input is going straight to the output parallel to the signal passing through the EQ. So every EQ move you make is parallel. Solo'ing a band will only solo the signal going through the EQ, but the other signal will be audible as well.
We've reported this issue to Steinberg many times, but since they will abandon VST2 soon I'm afraid they will not fix it. Please use the VST3 version instead, which works as it should. You can recognize the VST3 version by the /// symbol next to its name. Also the VST3 version is simply called "Pro-Q 4", where the VST2 version is called "FabFilter Pro-Q 4".