Noise with USB Audio DAC in Windows VM

[jpbaril]

Hi,

I did passthrough an usb audio DAC to a Windows 10 VM with this in console:
device_add usb-host,vendorid=0x08bb,productid=0x2704

Windows instantly recognized the USB DAC and then sound could be heard.

But there is a "static" noise.

Here is a sample. You can hear the "tic-tic-tic......." while Obama is talking.

https://www.dropbox.com/s/w3n46fhkhpyt76g/usb-dac.m4a?dl=0

On a normal Windows, Linux or Mac machine the sound is all fine.

The system says the DAC is a Burr-Brown pcm 2704.

What I find puzzling is that both on a normal Windows and in a virtualized Windows, the driver used is "Generic USB audio".

What could be the problem?

Thank you

 

[t.lamprecht]

Hi,

hard to tell, I'm not experienced in forwarding USB DAC to windows guest, but some general things.
It sounds like an buffer under run, with pass through working in general that should not be a problem of the Proxmox host, but rather hardware or guest specific, normally.

You are sure that the hardware isn't assigned/used to/by anything else in the host?

Quoting Stefane from the qemu mailing list.

[...]
There's a third possibility if you're using the ALSA sound system on
the host. Make sure no other applications are accessing the ALSA
device. This includes PulseAudio.

I've heard weird issues like this when multiple applications use a
sound device and change settings (e.g. sample rate) at the same time.
You can use pavucontrol to disable PulseAudio on the sound device, if
necessary.

Are there vendor specific drivers available? If yes try them, although with pass through it should work on VM or physical.

 

[jpbaril]

You are sure that the hardware isn't assigned/used to/by anything else in the host?

How can verify? I'm not at all used with audio on Linux.

Are there vendor specific drivers available? If yes try them, although with pass through it should work on VM or physical.

Not that I'm aware of. Texas Instrument site says that no drivers are needed and that OS should recognize the device. That's also my experience on bare-metal OS (Linux, Windows, OS X).

 

[t.lamprecht]

I could be a latency problem when passing through a single usb port, this is a bit tricky and audio is more sensible to such problems.

You could try to pass through the whole USB controller/bus where your headphone is connected via PCI passthrough, this assigns the device really directly to the VM and you can look if it's a problem of the USB passthrough only. Naturally all usb ports connectd to the hub are now controlled by the vm, but for a simple test it should be good enough.
https://pve.proxmox.com/wiki/Pci_passthrough

 

[jpbaril]

Passing through the whole USB controller makes it work correctly.

Thanks.

 

[justme]

Sorry for "waking up" an old thread, but I exactly the same issue with USB sound card and backend noise along with the sound. jpbaril, can you please explain the steps you have done in a more detailed way?

Thanks,
Mat

 

[zwehn]

I have the same Problem with the audio, even tried different usb sound sticks. Always the sam crackling , noise issue while playing

@justme google for proxmx pci passthrough.
Problem for this idea is that pci passthrough only works if your system support ioemmu which my msi cubi system do not support.
so I hope for another solution. Any other ideas?

 

[shinobiz]

Has the problem been solved?
I also encountered the same problem. Even the problem is 6.2-4.
According to the test, all integer multiples of 44.1Khz have problems, and integer multiples of 48Khz are normal.
This problem is the same in Windows and Volumio

 

[t-ice]

Hello to community members,
I am having the same issues with Volumio and Ubuntu.
Noticed that sound with bitrate of 256 kbps and lower works fine, but with anything higher than that it starts crackling. Using USB DAC from Burr-Brown which doesn't show any issues on other machines. Was playing around with iothreads, number of cores/cpuunits/etc, with no luck.
Has anyone found any solution to this or the only one is to run Volumio on dedicated hardware instead?

 

[leesteken]

Hello to community members,
I am having the same issues with Volumio and Ubuntu.
Noticed that sound with bitrate of 256 kbps and lower works fine, but with anything higher than that it starts crackling. Using USB DAC from Burr-Brown which doesn't show any issues on other machines. Was playing around with iothreads, number of cores/cpuunits/etc, with no luck.
Has anyone found any solution to this or the only one is to run Volumio on dedicated hardware instead?

If it uses the snd-hda-intel driver, it might help to enable MSI explicitly by adding options snd-hda-intel enable_msi=1 to a file in /etc/modprobe.d/. This often helps with HDMI audio too.

 

[t-ice]

If it uses the snd-hda-intel driver, it might help to enable MSI explicitly by adding options snd-hda-intel enable_msi=1 to a file in /etc/modprobe.d/. This often helps with HDMI audio too.

Used USB pass-through and PCM, but will give a try with intel hda driver over HDMI. Thank you, @avw

 

[richiewu]

Used USB pass-through and PCM, but will give a try with intel hda driver over HDMI. Thank you, @avw

have you tried, I have the same problem with volumio

 

[t-ice]

have you tried, I have the same problem with volumio

Unfortunately no luck, I was about to use it Volumio and ended up running it on RaspberryPi instead of VM.

 

[hyu]

I had the same issue on my Volumio VM and was able to PCI passthrough the whole usb controller. The proxmox docs made it surprisingly easy.