Audio Mixdown: thinks an External VST is in use even after Freeze

Cubase
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1

This is actually the second symptom of a bug I’ve reported to Steinberg before, to which I got a reply that that’s the way it’s supposed to work. No. No, it’s not.

Background: to use Cubase with an external synth or other MIDI thingee, you can either create separate MIDI and audio tracks or you can create an Instrument track, selecting “Steinberg | External Plugin | Cubase_MIDI_device_you_created_for_your_synth” as the VST. Instrument tracks have several advantages, including timing and level compensation, and only one track to deal with: you record your performance with MIDI, then Freeze the track to capture the audio - sort of like a very very handy Render In-Place.

When you Freeze an Instrument track, you are given several options, including “Unload Instrument when Frozen”. This is a very important option, because it releases those resources to be used on another track. If it’s a software VST, that free’s up RAM and CPU. If it’s an external synth, it free’s up that device (i.e., MIDI ports and audio channels), so you can use it on another track (Cubase allows only one instance of a MIDI device through “External Plugin” as described above.). I mean, that only makes sense, right? You’ve rendered the MIDI to audio; Cubase doesn’t need to hold onto those ports anymore.

HOWEVER, Cubase does NOT release the “External VST” devices after Freeze,even with the “Unload Instrument when Frozen” box checked. Steinberg tech support claims “that’s the way it’s supposed to work,” that doesn’t pass the laugh test. Why would it be designed to stay loaded, whether or not I choose to have it unloaded? It wouldn’t; this is a bug.

Today I found the second symptom of this bug, underscoring my point that this is NOT the way it is supposed to work. The second symptom of this bug is that, even when an Instrument track using an external synth is Frozen, Audio Mixdown insists that an external plug-in is being used, and therefore forces the render to be done in real-time.

C’mon, Steinberg, please fix the “Unload-After-Freeze” bug, such that External Plug-ins unload properly after Freeze, per the UI checkbox. These are more than just bugs; they’re loss of functionality.

2

Well, bugs can cause loss of functionality…

I can’t reproduce this. After freezing the external instrument, it renders it normally (not in real time) so here it does unload it.

3

Wow. OK, thanks for checking this on Windows. I will re-report it as a bug, apparently specific to Mac.

FWIW I’m running on a Hackintosh (Mac OS running on PC hardware) so have the option of running Windows, instead. This machine is dedicated to Cubase & Wavelab, both of which run both places, of course, so maybe I need to reconsider whether to switch back to Windows. Ugh. Switching is a pain. But I hear that Cubase actually performs better on Windows… SAD!! Apple seems to have thrown creative types under the bus, in favor of iPhone junkies.

4

Bumping this since there aren’t a lot of recent threads about those issues. I encountered this issue recently while trying to export a mixdown of a project that contained some external instruments in the Frozen state. The bug still exists in Cubase 13, and I did some more testing to detail the issue.

You’ve rendered the MIDI to audio; Cubase doesn’t need to hold onto those ports anymore. HOWEVER, Cubase does NOT release the “External VST” devices after Freeze even with the “Unload Instrument when Frozen” box checked.

This first part is by design. You do have the option to unfreeze a track, and this would cause problems if you’ve already used the external instrument again on another track since it would then be locked by that track.

The second symptom of this bug is that, even when an Instrument track using an external synth is Frozen, Audio Mixdown insists that an external plug-in is being used, and therefore forces the render to be done in real-time.

This is almost certainly a bug however, and I did some more testing.

Most importantly, if you freeze your external instrument tracks and then immediately do an audio mixdown, Offline (non-realtime) Mixdown works fine. Cubase understands that the External Instrument tracks are frozen and don’t need to be rendered in realtime. This is probably why the poster above was unable to reproduce the issue, even though it also happens on Windows (I’m running Win 11).

However if you exit out of Cubase and then restart it and reload the project, Cubase has forgotten that the External Instrument tracks are frozen. They still show up as frozen in the GUI , the MIDI notes are locked etc., however if you now try to do an audio mixdown, Cubase insists it has to be done in realtime since external plugins are being used. This happens even on an empty test project with just one external instrument.

I’ve tried multiple methods to “trick” Cubase into realizing the External Instrument tracks are in fact frozen, but so far the only thing that worked was un-freezing and re-freezing the tracks again (which is tedious). If you do un-freeze and re-freeze the tracks, Offline Audio Mixdown work again, but only until the next time you restart Cubase.

I’m currently trying to get support to re-produce the issue, but I don’t have very high hopes., Until then, External Plugin tracks are not very useful since you can’t actually do an audio mixdown if you use them (realtime mixdown is not an option). I also know you can bounce the audio to another track and disable/delete the external instrument, but that defeats the purpose of External Plugins, which is the convenience of having MIDI and Audio on the same track like a VST.