Slate Digital Virtual Mix Rack Bug

I suspect this is a bug with the plugin itself but wanted to post here just in case anyone else has seen this to make sure I’m not missing anything.

When I load Slate Digital’s Virtual Mix Rack then load a module with sidechain functionality (the 1176 module especially) into a track in Cubase, it seems like the audio from that track is routing back into itself and it phases out the sound(?) completely. If I click the track’s Arm to Record button, it monitors the sound and everything works fine, but as soon as I disable the Arm (unclick the red button), you see the meter on the module jump to max and the sound becomes garbled and fades out.

I’ve looked at all of my audio routing in Cubase and can’t see anything wrong. I’m using Control Room with my Studio Monitors (Main L+R) and my Headphone output (7+8) on my interface to listen through. My main output is not connected to any audio device:

Output Audio Routing:

Input Audio Routing:

Control Room Audio Routing:

Control Room Side Bar:

I have also looked at all of the audio routing in my project to make sure each track is routing where it should and have not found any issues there, either. I suspect this is a bug in the plugin but thought I’d double check here in case anyone has any thoughts.

I think I may have resolved this. I’m not sure if this is a Slate issue, but I did a fresh install of Cubase and thought that resolved the issue until I dropped VMR with an 1176 on a track last night to confirm and it happened again.

I went into the System Settings on the Mac, then into the Sound settings and reset my default System audio device back to my Klipsch speakers (running through USB). This seems to have resolved the issue.

From what I can tell, it looks like loading VMR (or potentially other plugins) is somehow hijacking the Mac’s default sound settings and not only sending audio through Cubase, but also through the Mac’s audio as well. Then it’s also picking up that doubled signal as an input, which effectively doubles the audio signal’s volume causing the plugin to overload.

After I ran into this with VMR, I removed it and loaded a Lindell 80 from Plugin Alliance and could see on that meter that I was hitting 12+ db if not more. If I disable the plugin, the audio hitting the stereo channel was much less, maybe -6db, so it’s not a gain staging issue.

When I went into the system settings on the Mac and essentially clicked on my interface and then back over to my Klipsch speakers, that seems to have resolved the issue. I’ll update here if it happens again and that doesn’t resolve future issues.

The issue came back and updating the Mac audio settings as much as I could didn’t help, but I do think I figured something out when testing some more. I submitted this to Slate Digital as well. I’m not sure if what’s triggering this bug is in Cubase or Slate Digital’s VMR, but here’s what I wrote back to Slate’s Support team:

I had the issue pop up again. Still not sure if this is on Slate’s side or if it’s something about how Cubase is routing audio, but I had a track I was working on, had VMR on a bass group from the very beginning and everything was running smoothly. I was working on a section without the bass playing then when I went to go back to play, the issue was there.

I don’t think the Mac Audio settings are at play - tried that trick and it didn’t work this time. However, I saved the track out to a new track that I was going to submit as a bug report and was playing around trying to see if I could get more information to help guide me to where I need to go to find a resolution, and found something interesting.

The default VMR plugin preset will still load and process the audio without any issues. As a test, I dropped a new instance of VMR in the insert chain before the problematic instance and was going to save copy of the track so I could open the Cubase track .CPR file to see if I could see what value is being affected when this bug occurs and it seems to have reset whatever audio value is causing the issue back to normal. Now my original problem track that I was working on this weekend is working fine again.

Based on my testing, what I think is happening, is when I load the VMR into the track with the default preset (Classic Strip 1), there is some value that affects the audio coming into the plugin that doesn’t change. However, when I clear that preset and try to load my own, for some reason, it’s also clearing a default input gain value for the plugin and replacing it with a much higher value when a module that uses sidechain is put into a slot. This seems to affect all input gains going to the insert channel going forward until I dropped a new instance of VMR with the default preset into an insert slot prior to the problematic version, at which point it seems to reset this value back to the default, normal value. Even after I removed that first instance of VMR with the default preset, the formerly problematic instance continued to work correctly. I don’t have sidechain enabled on this channel at all, so there shouldn’t be any other audio feeding that sidechain input from within Cubase.

In other words, it’s almost like Cubase is set up as:

Instrument Plugin → Effect Insert Gain Staging for plugins with Sidechain (this is the value that’s getting changed) → Effect Insert Plugin Sidechain Audio Input

Instrument Plugin → Standard Audio Routing → Effect Insert Plugin → Effect Insert Plugin, …, → Stereo Out Bus

When you trigger the track to record, it is muting one of those tracks, giving you the proper pre-insert track volume, but when you unarm the track for recording, it brings that doubled insert volume back up and the plugin goes silent again because it’s either phasing the audio signal since it’s being double or just becoming too loud to process any more.

I’m not entirely sure, but I did see it resolved when I put that VMR instance with the default preset into the slot prior to the problem instance/effects.

Hopefully this helps. I’m really not sure what is triggering this to suddenly break - I haven’t been able to reproduce that yet.