Sudden crackling during live show

Hey, i am Running VST live on Tour Right now, and I had some serious crackling tonight on a vocal stack. Everything was pre loaded. Also the parts. I just started and at later in the song it stopped. I run it on a MacBook Pro M1 Pro.
Buffersize at 256 samples. CPU running at maybe 20%. Im using an AUDIO4c for the inputs and a PlayAudio12 for the outs. Any idea how I could avoid that next time?

Most probably this has nothing to do with the audio hardware, but the plugins that you are using. Try to narrow which plugs consume too much CPU.

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But my CPU is running at around 20% most, according to VST live… shouldn’t that be totally okay?

The CPU display possibly does not show every peak. Crackling indicates very short peaks of CPU overload.
You may also try to reset audio, by default, the “Panic” function does that, you can set this in “Edit/Preferences/Audio/Panic Rest Audio Device”. If this cures the problem, it indicates that the audio system goes out of sync with the hardware; in that case, there is probably some other task interrupting the system. Make sure no other audio using software is running at the same time, that includes internet browser etc.

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Okay, thanks, I’ll check that!

Hi @musicullum,

thanks for mentioning this.

As far as I can say while still trying to get to know VST Live:

last year, when I started using VST Live, mostly to create structures for using them at later occasions (music presentations, etc.), I was surprised at how low the (accumulated 8-core) CPU load actually was (ca. 10 to 15 % in rather simple test projects, and never more than 20 - 25 %, at that time still on an ancient HP z400, while now using a slightly less ancient i7 3770 which has about 3 times the overall computation bandwith).

[-Testing the VST Live demo project-]

  • At first, the demo project “Ghosts Of The Ocean” ran terribly (ASIO, various buffer sizes below 192, no preload), for it had this intense crackling noise, starting at about 15 seconds into the song.
    At first, I couldn’t get rid of it, as no lower ASIO buffer size seemed to work, and even at buffer size 192 there was the occasional crackling. No matter which sample frequency / bit depth, or which USB audio interface (all using either a USB 2 or USB 3 port). So, to be on the safe side, I chose either 10 or 20 ms latency, here no crackling at all happened.

  • Performance went 100% smoothly “out of the box” only when using the ASIO Generic Lower Latency Driver (at 48 KHz, 24 bits, 10 ms latency / 960 buffer size), here the crackling noise was (is) entirely absent, so no problems with any effects or VST plug-ins.

  • Again, and after switching back to UR824’s ASIO driver, performance at buffer sizes far below 192 / less than 128 was a small fraction better when running that VST Live demo project from one of the SSDs (SATA3), instead of running it from my main recording HDD (Seagate 24/7, SATA3).

[-ASIO driver performance / Demo project-]

  • Even after switching all used plugins (HALion Sonic 3.x / 7.x and Padshop 2) on and off, and also after switching on and off every used effect, it seemed to me as if significant performance problems can arise at buffer sizes lower than 128 and with the VST Amp Rack on, somewhere between…

    • Vers II (Stacks included)” / “Chorus Guitar” and…
    • Chorus II (Stacks included)” / “Tremolo & Phaser”.
  • Windows Task Manager didn’t (or doesn’t) show any obvious spikes, though. Once I switched VST Amp Rack off, the crackling got significantly better, but it didn’t disappear entirely, no matter which ASIO buffer sizes below 192 I’d set.

I do really like the song performance based concept of VST Live (and I do like the program in its entirety), yet in my case (and with my limited / outdated gear) the ASIO performance at buffer sizes lower than 192 is a bit more critical than I’d expected (but - nevertheless - can be compensated by taking adequate action). Meanwhile, I also suspect my graphics card to be part of the problem: once there’s too much GUI related “bling-bling” (mixer - fader meters, additional lower zone track head running simultaneously, etc.) then various degrees of crackling can occur (btw. on my machines, any Windows shell / GUI animations are always turned off).

  • (Current basic specs: Core i7 3770, Win 10 Pro 22H2 - 24 GB DDR3 DRAM @ 800 MHz -
    GPU: AMD R7 370, latest possible driver 22.6.1 - UHD screen via DisplayPort @ 60 Hz)

I always thoroughly audio-optimize my PCs (as far as I’m able to, that is - without external measurement gear, and of course incl. having set the Windows power scheme to max. performance), and there are somewhat less performance problems of this sort within Cubase 12, WaveLab 11, Dorico 5, or with any multi-media player software.

(-my apologies for the length of this post-)

Best,
Markus

[-edited: typos, readability-]

No problem!
All we can say is that VST Live does close to nothing when no plugins are involved. Of course, playing back hundreds of audio tracks would sum up to some significant amount of CPU usage eventually.
You can easily check that by starting an empty project.
ASIO drivers do tackle the CPU differently, and that adds to the pile, but usually this is also not of much concern. An interface with many I/O channels needs to process those in the first place when enabled.
The more likely causes for significant differences with ASIO drivers are external influences. You mentioned the graphics card; especially on older systems (or hardware), some graphics drivers block the entire system in order to acheive good benchmarks for certain games, which may interrupt audio processing, or give audio too few time to perform its tasks. Or, a sytem or external service gets in the way. These cases are often hard to analyse or even solve. In any case, for Windows, you should make sure that “High Priority Mode” is checked in Preferences/Audio.

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Latency monitor is great app for checking these kind of issues. Mostly it is graphics card and network card. My problems with dpc spikes goes away by disabling network. It’s not a big deal as I have a short cut for it on desktop

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You may try again with the next version (presumably, Friday), we made some changes that might improve the situation.

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