FabFilter User Forum
REAPER Oddities
It could be a coincidence but as soon as I started using Pro-Q4, I found some cases where items that have have Pro-Q4 on them sometimes don't pass audio immediately and the first hundred milliseconds or so is silent.
So far I have not found a pattern to provide more info but I'm wondering if this could be a Pro-Q4 thing. I'm on macOS Sonoma and was using the AU version in REAPER.
I just tried moving to the VST3 version but now, when I choose Pro-Q4 in the Item FX chain, I get an audio disruption every time the GUI opens.
Please let me know if you think either of these things (especially the 1st issue) can be solved so I don't have to roll back to Pro-Q3.
Justin Perkins — Apr 22, 2025
To clarify, "the first hundred milliseconds or so is silent" pertains to audio playback as this is audio I'm playing out to my analog processing chain.
It has nothing to do with rendering audio.
If the first problem is Pro-Q4 problem, the VST3 version does it as well.
I'm rolling back to Pro-Q3 to see if the issue goes away and can more confidently be pointed to Pro-Q4 or if it's something else.
Hi Justin,
We're not familiar with this issue. Could you provide some steps to reproduce?
What OS and Reaper version are you running?
Hi Ralph,
I am on macOS 15.4.1 and using REAPER 7.36
My sessions are at 96k.
For sure, the issue of the VST3 version causing an audio disruption when you have an Item FX chain of a few plugins, and then click on the Pro-Q4 to make EQ changes exists while audio is playing. That has never happened to be before with the AU version of Pro-Q3 or Pro-Q4 but as soon as I tested the VST3 version I noticed this.
Unfortunately, the VST3 version of Pro-Q4 did not solve my initial issue.
I'm still not 100% sure the issue is related to Pro-Q4 but I have now just reverted to Pro-Q3 to see if the issue goes away or not.
I will have more test cases in the next day or two.
I'll report back if that issues goes with Pro-Q3 or if it's something else not related to FabFilter.
The scenario when the initial issue happens is this:
I have a few items lined up on a single track. Those items have Item FX on them (a mixture of plugins, brands, etc).
There has never been an issue before but recently, when playing the session from start to finish, the first few hundred milliseconds of audio is not played correctly.
I'm playing audio from that track, out to an analog processing chain and recording back in. The recording is not the problem, it seems that the playback is the issue.
So far, after reverting to Pro-Q3 yesterday morning I have not experienced the main issue.
I need to do a few more days of testing to say for sure if I suspect Pro-Q4 as being the culprit.
This thread can be deleted. The issue where there is an audio disruption when opening the GUI during playback using the VST3 version does exist, but my original issue that caused me to even try the VST3 versions instead of the AU version has been determined to be a REAPER regression that will be solved with the 7.37 update.
Hi Justin,
thanks for letting us know!