XHCI and USB Audio perspectives

[Mikhail]

Greetings, dear community.
Please tell me what prospects to get UAC1/2 support for controllers without EHCI support.
As far as I understand now, the problem is the lack of isochronous support in the current drivers.
At the moment, there are more and more boards with controllers that support only XHCI interfaces, sound devices in USB ports do not work on such boards.
Does no one output sound via USB?

[Lars]

AN USB 12.13 drivers should support isochronous endpoints with XHCI controllers. Have you tried the AN drivers ?

David had contacted me that there *might* be problems with USBAUDIO.SYS / USBAUD2.SYS in conjunction with XHCI but he was not 100 % positive, therefore you should give it a try.

[Dave Yeo]

If they don't work and you have a current AOS subscription, you should open an issue. David is pretty responsive and often will fix things

[Neil Waldhauer]

The USB audio driver worked with my XHCI only system a while ago in testing.

Recent advances in Uniaud made USB sound unnecessary on my systems.

[Lars]

Mikhail is looking for something that supports sample rates well beyond 44.1 kHz and also 32-bit sample depth. Uniaud cannot do that, partly because only USB AUDIO knows about those new PCM sample formats and partly because Uniaud on board HW does not support that.

[Mikhail]

After installing the latest driver 12.13 into my system, UAC2 audio devices did not work through the ports of controllers with pure XHCI mode.
At the same time, the absence of any errors seemed very strange to me. In fact, there is simply no sound, playback does not start. PM123 player or the built-in player tries to start WAV file playback and that's it, the timer hangs at 00:00 there are no errors, you can switch tracks, do whatever you want, there is no sound.

[Mikhail]

Mikhail is looking for something that supports sample rates well beyond 44.1 kHz and also 32-bit sample depth. Uniaud cannot do that, partly because only USB AUDIO knows about those new PCM sample formats and partly because Uniaud on board HW does not support that.

Lars, thank you for the clarifications and your support.

I'm not really looking for quality in PCM formats above 44.1Khz/16Bit.
Yes, recordings in 96kHz/24bit or 192khz/24bit formats can sound good.
But even in 44.1Khz / 16Bit PCM there is a huge amount of information that is not audible if you connect an amplifier, speakers or headphones directly to the analog output of the computer's sound card.
In order to transmit an audio signal from a computer to an external, higher-quality DAC (digital-to-analog converter), you need to use either: USB bus (USBAudio), or AES/Coax or i2c LVDS (Uniaud).

• The first option is really universal, it allows you to transmit any audio format, no additional expansion cards are required, as long as you are satisfied with the power quality and other port parameters on your motherboard.
• The second option only in the i2s version gives universal support for all audio formats, requires the installation of an expansion card with an output port.

There are very few digital signal output cards for a computer, there are only a couple of pieces for i2c output (there are also not many devices that will receive an i2c signal).
For this reason, there is no alternative to USBAudio for high-quality audio output yet.
OS/2 outputs extremely high quality audio.
If simple conditions are met, it is possible to receive a signal better than that of specialized devices from DCS, Aurender.

[Andi B.]

There are very few digital signal output cards for a computer

All my systems have SPDIF. I think this is usual for desktop PCs.

[Mikhail]

Indeed, SPDIF is found on some motherboards, both in the Toslink (Optical) and Coaxial versions.
But there are fewer and fewer such boards, now digital audio is mainly encoded inside HDMI or DP, for transmission to AV receivers.
Of course, this method of signal output is better than analog.
Comparing the sound quality after a DAC that has both SPDIF and USB input is not in favor of SPDIF.
The decrease in quality at the output of SPDIF after cheap motherboard chips has quite understandable reasons, but I think it is wrong to describe them here.
Again, supporting only a very limited set of audio formats in UNIAUD is a significant problem.

[Lars]

I cannot promise but David pointed me to some potential issue with XHCI where a change to the audio driver might be necessary. I am off for two weeks, thereafter I'll try and build a test version of USBAUD2.SYS.

[Mikhail]

Hooray.
Hope is the best I could get.
Thanks for the perspective.

[Lars]

Hi Mikhail,

find attached a test version of usbaud2.sys. Just save the old files and copy these to the \mmos2 directory.

[David McKenna]

 Hey Lars,

 Finally got my Behringer UMC202HD back from being borrowed and tried your test driver with the ArcaNoae 12.13 XHCI drivers (on a XHCI only system). Unfortunately, couldn't get any sound out of it, and MP3's don't even start to play. I'm willing to do some testing if you want...

Regards,

[Mikhail]

same result

[David McKenna]

 Hi Mikhail,

 Does your device appear in the hardware manager or USB resource manager when you plug it in? Mine does not, so I opened a ticket at ArcaNoae...

Regards,