VM Audio has a crackling/pop sound.

[whocaresuserame]

Hi all, it seems that this is a common problem with no solution? or I may be reading it wrong.

I have a Windows 11 VM with GPU and two USB cards as PCI pass-through. Everything works flawlessly except for 1 thing. The audio.
Everything I play will playback without pause or latency, but I hear constant crackling and popping sounds as the audio plays.

I have tried to move the headphones over to another PCI pass-through device as well as the monitor's headphone jack just in case the issue was a singular USB PCI device.
However, the results have been all the same. I tried different headphones as well.

I have no idea what could be causing the issue especially if I am giving a dedicated PCI pass-through. Of course, I may not be unaware of a specific reason that may be causing this.

Any help and insight would be appreciated.

Also, all PCI passt-hroughs are done through the Proxmox web interface and Proxmox is installed on bare metal.


The issue was fixed, follow the thread to see what I did.

 

[leesteken]

Did you enable MSI in Windows? That usually does the trick. I don't use Windows, so I don't have a reference or link at hand.

 

[whocaresuserame]

Did you enable MSI in Windows? That usually does the trick. I don't use Windows, so I don't have a reference or link at hand.

I am not entirely sure what this means. In my own understanding, MSI means Managed Service Identity and its only for Azure. Or MSI as in the installer. Could you elaborate to what it is?

NVM I found it and will look into it https://learn.microsoft.com/en-us/w...g-message-signaled-interrupts-in-the-registry

 

[leesteken]

NVM I found it and will look into it https://learn.microsoft.com/en-us/w...g-message-signaled-interrupts-in-the-registry

Here are some other related forums: https://www.reddit.com/r/VFIO/comments/ibmjs3/finally_fixed_crackling_audio_when_passing/ and https://forum.level1techs.com/t/win...ks-for-audio-and-improving-performance/130620

 

[whocaresuserame]

Here are some other related forums: https://www.reddit.com/r/VFIO/comments/ibmjs3/finally_fixed_crackling_audio_when_passing/ and https://forum.level1techs.com/t/win...ks-for-audio-and-improving-performance/130620

This provides the answer to doing it https://forum.proxmox.com/threads/usb-keyboard-and-audio-issues.104472/

I enabled MSI on my USB PCI devices and audio devices and restarted the VM and there is still some static and pops however its not as bad. I'm sure if I spent more time trying to find what all devices do and are I will be able to figure it out. for now this is good enough.

 

[leesteken]

This provides the answer to doing it https://forum.proxmox.com/threads/usb-keyboard-and-audio-issues.104472/

I enabled MSI on my USB PCI devices and audio devices and restarted the VM and there is still some static and pops however its not as bad. I'm sure if I spent more time trying to find what all devices do and are I will be able to figure it out. for now this is good enough.

Did you already do all the other best practices to improve Windows on Proxmox like the VirtIO drivers, using VirtIO SCSI Single and enabling IO thread?
Also, don't give the VM more virtual cores then you have real cores (don't count Hyperthreads!) and preferably a little less, to improve latency.

 

[whocaresuserame]

Did you already do all the other best practices to improve Windows on Proxmox like the VirtIO drivers, using VirtIO SCSI Single and enabling IO thread?
Also, don't give the VM more virtual cores then you have real cores (don't count Hyperthreads!) and preferably a little less, to improve latency.

Here is some info on the device

hostpci1: 0000:07:00 is the USB card where I have an audio adapter.
The CPU is under 60% on average its resides between 13%-20%. So I believe its fine. I have an i9 13900k

agent: 1
bios: ovmf
boot: order=ide0;scsi0
cores: 4
cpu: host
efidisk0: VM-Storage:101/vm-101-disk-0.qcow2,efitype=4m,pre-enrolled-keys=1,size=528K
hostpci0: 0000:0a:00,pcie=1,x-vga=1
hostpci1: 0000:07:00
machine: pc-q35-8.1,viommu=virtio
memory: 12288
meta: creation-qemu=8.1.5,ctime=1714690890
name: Win11-Main
net0: virtio=BC:24:11:C6:40:28,bridge=vmbr0
numa: 0
onboot: 1
ostype: win11
scsi0: VM-Storage:101/vm-101-disk-1.qcow2,size=150G
scsi1: Extra-Storage:101/vm-101-disk-0.qcow2,size=500G
scsihw: virtio-scsi-pci
smbios1: uuid=8f979966-c54c-4c68-904f-d1031b928ca3
sockets: 1
tpmstate0: VM-Storage:101/vm-101-disk-2.raw,size=4M,version=v2.0
vmgenid: e44eeacf-d00d-4998-be66-353175099cf7

as for "VirtIO drivers, using VirtIO SCSI Single and enabling IO thread?" Yes, except for "enabling IO thread" I am not 100% sure on that one. looking at the virtio drivers from the iso I had to use from https://pve.proxmox.com/wiki/Windows_VirtIO_Drivers I dont see any that relates to sound.

But for the basic best practices I'm sure I got it all.

 

[whocaresuserame]

Hi to anyone who reads this.

I did as leesteken had mentioned about MSI and what this post mentioned as well https://forum.proxmox.com/threads/usb-keyboard-and-audio-issues.104472/post-506649

I did it to my USB PCI pass-through, the HD audio for my Nvidia GPU. When I went to the Register edit the first time and enabled MSI on the devices, and if they didn't have it enabled I added it.
I want to note that after I did everything I restarted the VM and wanted to confirm that the changes I made worked, However, I noticed that there are 2 new locations to get to the devices
Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet
and
Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet0001

With the same branch to get to the PCI directory.. I wasn't sure why another directory was duplicated after the restart. However, I went to them and enabled MSI on all the devices I had mentioned since they were turned off in the duplicated directory while the old directory kept the changes I made.

After that, I used the Virtio ISO to follow the best practices of installing the drivers despite me believing that I had already done that because we are all human and we may be wrong, so it doesn't hurt, despite seeing the drivers installed in the device manager.

After all that I shut down the VM from proxmox, waited a bit then started it up again. The sound static/pop sound still continued for a bit, but it was dampened and less noticeable then before. However, after 1 hour I noticed that the annoying sound was completely gone. I'm not sure why the delay occurred, but I did fix the issue I was complaining about.

 

[javito1081]

Hi to anyone who reads this.

I did as leesteken had mentioned about MSI and what this post mentioned as well https://forum.proxmox.com/threads/usb-keyboard-and-audio-issues.104472/post-506649

I did it to my USB PCI pass-through, the HD audio for my Nvidia GPU. When I went to the Register edit the first time and enabled MSI on the devices, and if they didn't have it enabled I added it.
I want to note that after I did everything I restarted the VM and wanted to confirm that the changes I made worked, However, I noticed that there are 2 new locations to get to the devices
Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet
and
Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet0001

With the same branch to get to the PCI directory.. I wasn't sure why another directory was duplicated after the restart. However, I went to them and enabled MSI on all the devices I had mentioned since they were turned off in the duplicated directory while the old directory kept the changes I made.

After that, I used the Virtio ISO to follow the best practices of installing the drivers despite me believing that I had already done that because we are all human and we may be wrong, so it doesn't hurt, despite seeing the drivers installed in the device manager.

After all that I shut down the VM from proxmox, waited a bit then started it up again. The sound static/pop sound still continued for a bit, but it was dampened and less noticeable then before. However, after 1 hour I noticed that the annoying sound was completely gone. I'm not sure why the delay occurred, but I did fix the issue I was complaining about.

Cant find anywhere to do the MSI solution, can u pls post a link on how to do the registry thing? cause im having the same issue with the graphic card hdmi sound :-(