Rack v1.1.6 hangs when trying to change Audio Device

I’ve been away from the rack for a while but when I returned and loaded a patch I had to change the audio device. Using DirectSound I clicked on Line Out 11/12 (Soundcraft Signature Series 12MTK) (1-2 out) and rack hangs. If I restart and try and change the audio driver on Audio-8 to ASIO - it hangs.IN fact, if I try changing anything in Audio-8 it hangs, or rather it’s not responding with CPU showing as 55%.

I tried to use Audio-16 but that crashed. log.txt (152.6 KB)

I’m having the same problem with Rack v1.1.6 on macOS Mojave 10.14.6 using a MOTU ultralite AVB. When I try to switch audio channel in Audio-8 Rack hangs, and when I force quit and restart Rack and immediately try to delete Audio-8 it hangs.

More details: When I only have one Audio-8 everything works fine and I can switch between AVB audio outputs 1-8 and 9-18, and change sample rate. When I create a second Audio-8, because I want to use channels 1-18 so one Audio-8 is for channels 1-8 and the second is for 9-16, it is on the second Audio-8 that I have problems. I can select the AVB, but when I try to set the sample rate Rack hangs and I have to force quit. On restart the I get the same two Audio-8’s I had when I force quit, but Rack hangs when I try to delete the second one. I have to start with a new patch to avoid another hang.

Restarting with a new patch, the Audio-16 works fine and gives me the channels I need.

Moral: don’t have two Audio-8s.

in VcV Rack version 1.x.x more “audio/interfaces” modules are not supported within the same patch. sometimes on linux it works, but it should not, so we take it as it is :wink:

Sometimes it happens to me too, if I try to change the device/interface VcV Rack hangs or crashes, so I always load a new “audio/interface” module, and leave it blank. Then I blank the old one, then move the cables, and set the new device on the new module.

1 Like

I don’t believe it’s related to multiple Audio devices. The problem occurs with an existing patch with one Audio-8. If I try and delete the device, Rack loops (55% CPU) and is unresponsive.

I was able to create a new patch using VCO-1 and Audio-16 but that only works with ‘Directsound’ and not ASIO - although it recognises the Soundcraft ASIO driver.

In fact, besides the ASIO issue, new patches seem to be OK with Audio-8 and Audio-16. It seems to be just existing patches that cannot be changed.

If an Audio module setup calls up channels that are currently in use by the system, rack will hang.

Rack expects the 8 channels that are being addressed by Audio-8 to be free, as not in use or not assigned anywhere else.

Unfortunately (in this case) this is the way VCV Rack works.

I’m not sure what you mean by channels but I can use Rack for new patches and, after downloading both a new patch (3 days old) and old patch (3 years old), existing patches. So I now suspect that the failing patches may be somehow corrupt, which would be very annoying.

It should be noted that if you have no audio device at all, such as when you have just deleted the Audio-8, rack does not run in real time. It’s the audio device which synchronises the audio thread. Without it, rack can use considerably more cpu at times, and this is expected behaviour in v1

1 Like

I forgot to say that I always check to have the same settings (for example 44100 Hz / 512 samples) in 3 different places: audio device (operative system) + VcV Rack (menu) + audio module

I would compare a working patch and a “corrupted” patch in an editor, they are simple Text files and maybe you can find some hints there, should be in the first lines.

But maybe the “corrupted” patches just try to load some old modules that are not present or are buggy.

Thanks for the editor suggestion rsmus7. The source code of the old patch was ‘old’ but did generally resemble the new patch. What I did do though was to edit the device name in to old patch to match the new patch (as shown below), and It’s all working now!

Note that if I try and change the device name to ‘no device’ it all starts locking up again.

  "plugin": "Core",
  "version": "0.6.2c",
  "model": "AudioInterface",
  "params": [],
  "data": {
    "audio": {
      "driver": 8,
      "deviceName": "Line Out 11/12 (Soundcraft Signature Series 12MTK)",
      "offset": 0,
      "maxChannels": 8,
      "sampleRate": 48000,
      "blockSize": 512
  "pos": [