VCV Rack f*cks up my sound interface?

I have been experiencing some problems with my sound crackling (using a Focusrite Scarlett). It seems to start with large patches in VCV Rack, but the strange thing is that it persists even after closing VCV Rack and restarting the computer. The sound crackles when playing sound from youtube and spotify (VCV Rack not even running).

I have some technical knowledge about computers, so it seems very weird to me that a program can affect the sound even when not running and after a reboot. However, I didn’t have this problem before I started using VCV Rack, and every time this problem appears it has started by loading a large patch in VCV Rack which as initialized the crackles (and those crackles persist when trying to play other audio)

I have ran a latency monitor and I seem to have DPC issues. VCV rack doesn’t come up in any way in that monitor.

Is this just a coincidence, or is there a possibility that VCV Rack somehow does something by interacting with the sound drivers or something?

I know this is a longshot, but I have been in contact with Focusrite support which cannot help me, and I am getting kind of desperate, so I am hoping someone might have had the same issue and have a solution for it.

if you used latencymon, and it shows that you have dpc issue’s then there is already your answer.

the problems might only have become evident after using vcv rack, they would have become evident at some other point. regardless of what software you use.

Focusrite drivers are not at all great in handling multiple applications audio all at the same time. There is an option if you are on windows for applications to take explicit control over the device, having this ticked is inherently bad most of the time.

Came across a similar issue just the other day when I loaded a DAW while a silverlight app was using the driver, massive buffer issues appeared in the silverlight app and persisted even after a system restart. The only thing that fixed that for me was updating the driver.

Focusrite support is pretty bad from my experience, driver updates from focusrite caused a few blue screens for me, after contacting support their first email back was ‘this is not a driver failure something else caused the issue’, suffice to say my next interface will not be from Focusrite!

I’d see if there is a driver update available for your interface and retest with latencymon.

Your issue sounds very similar to mine! My interface is pretty new, so I can return it. Maybe I should do that… What would your next interface be? :wink:

Well, the question is if VCV Rack is somehow causing the the problem and if there is something I can do about it (other than not using VCV rack :’( )

Not too sure, should have got that Mackie Big Knob.

Would love to get a MOTU or RME but it will probably be restricted to budget next time also.

There definitely seems to be some kind of issue with VCV Rack, though. Because if I run it through the bridge into FL studio. There is a complete process overload and crackling, but it stops as soon as I stop the patch. If I take the same patch and route it to my device through ASIO instead, I get persistant crackling.

So for now, It seems the solution is to run it bridged (unfortunately that takes up a lot more resources, so I have to make smaller patches)

if you’re using bridge, make sure to increase the block size in your DAW, as this option in Core> Audio gets locked, and is often WAAAAY too low for Rack.

Looks like this is called Buffer Length in FL Studio. Go for a power of 2, starting with 4096, and lower it until you lose stability. Also, apparently there’s a triple buffering option?!? maybe check if that one helps/hinders.

(my source:

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@Eurikon from here?

Awesome tips about the Buffer options. Suddenly there is no CPU spike when using bridge :slight_smile: I will use it bridged from now, and hopefully avoid more sound issues.

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The linked latencymonitor is what I used

doublecheck your ASIO settings as well - direct out of Rack, use the same block size in Core > Audio that you would in FL Studio, as well as any separate ASIO settings…

(I’m not too familiar with ASIO, I’m a WASAPI person right now, bc my slapchop is a bit of a potato)


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You might want to go through this book also to squeeze the most out of your setup. Well worth the read!


Vcv rack is a nightmare on processor, i upgraded my machine because of it. It had my macbook processor running at 153% after like the 2nd.voice. it was a little older (though I’d never had problems) so I got a PC with an AMD Ryzen 5 3600. Doesn’t bother the processor anymore. But now the audio is just terrible. First 2 or 3 voices its fine, but once we get some drums going and blob reverb and stuff it deteriorates into slightly beepy static that is somewhat musical. Im using a zoom h4n as an interface, i switched to my sound card, much worse. My point is vcvrack is like a software miracle with how it emulates eurorack and all those modules. But usually that level of awesomeness comes with a price. I think the price for vcvrack is an expensive top of the line interface on a resource rich computer.

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That isn’t true in general. I’m sure you’ve seen videos where people use hundreds and hundreds of module with no problem. It’s true it doesn’t run well on really weak computers, and it tends to make non-gaming laptops overheat and slow down.

Perhaps you have one or two (or more?) plugins that you use a lot that eat up an enormous amount of CPU? Turn on the CPU meters in rack, find who the problem is, and get rid of it.

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that’s a big question. On windows many people say the Focusrite have bad drivers. For “affordable” interfaces on wndows, many people say the Steniberg ones are good.

You can try turning off your Focusrite’s inputs in Windows’ recording devices menu. Worket for me with the Scarlett. I don’t think it’s a VCV Rack related issue. Sometimes the audio is being turned off while watching something through the browser. Some noise is popping up and there is a need to turn it on then off in the playback devices. You may try running audio through a DAW like Reaper. Works perfectly fine and it’s fun :slight_smile:

I don’t think this is true,

I use a PC with an Ryzen 7 1700 and a GTX 1050 graphics card with 16gb ram, and a cheap Behringer UMC4040 HD audio interface, and I have almost never any problems with huge patches in VCV, I can also do screen recordings with OBS and it is working fine.

So maybe you need to check your setup?

which framerate are you at?

which graphics card/drivers do you use?

which soundcard drivers do you use?


If you would like some help please provide some more info about your system setup.

I found the FL Studio ASIO driver very usable with my hardware. But it goes only to a block size of 256. Still I can use the WASAPI driver with a block size of 64.