Async USB Dac Experiments - testers wanted...

[dsdreamer]

@RadBadMark good that you could share that info.

The only Arcam DAC that I know of that supports USB 2.0 audio is the D33. You seem to have something that is bus powered and yet accepts USB 2.0 audio @ 192kHz. The rDACs don't go above 96kHz USB audio 1.0.

With which DAC did you conduct your tests? Or would you have to shoot me if you told me?

[Mnyb]

Is not 192k converted to 96k by the server ( with the eminent help of SoX ) .

Even with this special kernel ?

[RadBadMark]

> Is not 192k converted to 96k by the server ( with the eminent help of SoX ).

I can say for definate that Sox was not happening server side.

> With which DAC did you conduct your tests? Or would you have to shoot me if you told me?

Something like that The D33 will be my next test.

[Triode]

Asynchronous class 2 audio appears to be working well, although using your applet to change the soundcard doesn't work for me for some reason - when I select the USB DAC in the menu and the SBT reboots, it enters a continuous boot loop until I unplug the DAC, at which point it then boots normally and I can change it back to the default soundcard. To get round this I've selected the USB DAC by modifying asound.conf instead - I'm assuming this amounts to the same thing although I obviously don't have the the info from the app available. Can I get hold of this data elsewhere in the system?

Thats very good progress - thanks for testing. By modifying the asound.conf layer you are going through a layer of alsa which I had hoped to bypass by targetting the device directly.

I think the problem is that the sound card is expecting format 0xa which is not supported by the main squeezeplay code at present (only 16 and 24 bit mode are). I will need to look at adding this to the jive_alsa code which is something I had hoped to avoid.

I'm using test kernel 4 and it's been running in the background now for a couple of hours with no noticeable clicks, pops or dropouts. I'm not connected via a hub either, the DAC is bus powered and plugged straight into the back of the touch. Seems quite happy playing 44.1/48/88.2/96/176.4 & 192kHz off the server too, although I don't know what the SBT is doing internally. I should be able to verify output sample rates tomorrow as my other DAC has sample rate indicators

As its a high speed device, I believe it should work directly connected to touch (its only the 2<->1.1 portion of the touch silicon which appears to have a limitation). Can you see the momentary frequency changing - this would indicate async is working correctly.

[Triode]

Mark - could you post the dmesg for when the audio stream is started? (I'm not sure I enabled debug on that kernel, but would be useful to see what it records). Do you know if the dac only supports S32_LE format over uac 2?

[RadBadMark]

I did look at dmesg but couldn't spot anything relevent so I didn't post it, I'll check again later though. I don't know about sample formats off the top of my head but I'll see what I can find out.

[Triode]

I did look at dmesg but couldn't spot anything relevent so I didn't post it, I'll check again later though. I don't know about sample formats off the top of my head but I'll see what I can find out.

Ok - no worries. Can you pm me an email address. I will update the binary to support S32_LE and let you have it to validate.

[Triode]

Based on Mark's feedback I've updated the Usb Audio Output applet to version 0.6. This should now support detection and selection of dacs wanting 32bit samples. This is working for Mark with kernel #4 to support uac 2 dacs. Anyone else with a uac 2 dac may wish to try this combination and post here.

[MWelschenbach]

Based on Mark's feedback I've updated the Usb Audio Output applet to version 0.6. This should now support detection and selection of dacs wanting 32bit samples. This is working for Mark with kernel #4 to support uac 2 dacs. Anyone else with a uac 2 dac may wish to try this combination and post here.

Kernel #4 with USB Audio Output applet version 0.6 plugged to my 8200CDQ play hires material (96/24) without any flaw.

[jackocleebrown]

Hi Triode,

Many thanks for your work on this!

I was wondering if you could give me a little help, I'm trying to get the Arcam r-dac to work. It uses the tas1020b streaming controller internally.

I've tried all four of your kernels with and without a usb2 hub and all have the same behaviour: I go through your setup instructions and at point 7 the touch reboots once I have selected the rdac but then it gets stuck in a loop and continually reboots after around 20 seconds of showing the "free your music" splash.

Similarly to RadBadMark, if I unplug in the DAC then the boot works ok and I can select then normal config from the USB applet menu.

I tried to set asound.conf to use the DAC but this results in the same rebooting loop. If I hotplug the DAC with my modified asound.conf then try and play a track then I get no playback and dmesg includes the line:
"ALSA sound/usb/clock.c:227: 2:1:1: cannot get freq at ep 0x1"
which may be relevant.

It was mentioned earlier in the thread that one solution to this type of issue may be editing the file /etc/squeezeplay/userpath/settings/SqueezeboxFab4.lua to set a different bit depth. I've tried this and it does not help, however whatever changes I make to that file seem to be overwritten on/etc/squeezeplay/userpath/settings/SqueezeboxFab4.lua a reboot.

Any help is much appretiated.

Thanks, Jack.



# cat /proc/asound/DAC/stream0
ARCAM ARCAM DAC at usb-fsl-ehci.0-1, full speed : USB Audio

Playback:
Status: Stop
Interface 1
Altset 1
Format: 0x20 (24 bits)
Channels: 2
Endpoint: 1 OUT (ASYNC)
Rates: 32000, 44100, 48000, 88200, 96000
Data packet interval: 1 ms
Max Packet Size = 585
EP Attribute = 0x1