HDMI multichannel audio on Linux NUC

I’m trying to get Roon’s new multichannel audio working over the HDMI output on my Intel NUC (Skull Canyon). There are lot’s of audio devices available, :

I can play 2 channel audio well. However I can’t configure the device as multichannel:

I’ve got a feeling that this is a linux / also configuration issue - but I have no idea where to start with that. Any help would be appreciated.

Here is the output of alas-info.sh

And the output of aplay -l

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC233 Analog [ALC233 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 1: ALC233 Digital [ALC233 Digital]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
Subdevices: 0/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 8: HDMI 2 [HDMI 2]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 9: HDMI 3 [HDMI 3]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 10: HDMI 4 [HDMI 4]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: B20 [Benchmark DAC2 USB Audio 2.0], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0

Any help here?

I’ve spent some time debugging this and my computer can output multichannel over HDMI:

speaker-test -c6 -D hw:0,3 -r48000

Produces sound to all the appropriate channels. This is the sound device that I am using to output 2 channel audio to in Roon. So it seems the issue is that Roon isn’t recognizing the HDMI as capable of supporting multichannel.


@Eric or @brian can you please have a look and comment on this?

TL;DR I’ve confirmed that my NUC can output 5.1 sound (via the speaker-test command). But I can’t select 5.1 as a Channel Layout in Roon. This is a Skull Canyon NUC connected via HDMI to a Denon X4200W receiver.

Yes, this is being worked on. We’ve been iterating with one of our alpha testers, since he has a setup like this. A fix is coming.

Super, thanks.

Great news, thanks for the update.

Hi Roon team. I just tried out the 208 build. I can now select 5.1 as a choice for my HDMI output, however when I try to playback sound I get an error:

Transport: playback_error_endpoint_device_init_failed

Which you can see on the screenshot below:

I’ve confirmed that it works fine with 2.0 output.

Thanks in advance for the assistance.

For HDMI you probably need to run in 7.1 mode. Most of the drivers we’ve seen won’t accept 5.1 PCM and do something reasonable with it.

That worked, thank you!

I’ve been listening to SACDs & DSD for 15 years and for the first time ever I’ll b able to listen to the multichannel versions.

1 Like

so what is the minimum hw spec for a intel nuc to act as a multichanel endpoint?

Jumping into this thread to get updated info since no one replied to @John_Smith question. I’d like to be able to play my 5.1 multichannel files to my AV Receiver and leverage my surround system. I had hoped this would be possible using an Apple TV 4k but it appears not to be (wishing for a Roon Apple TV app!). So my only next choice seems to be an Intel NUC with ROCK installed and HDMI to my Anthem receiver. I assume this would work now in 2018. Any minimum requirements for this? I’d like to buy a used NUC as low spec’d as possible to reduce cost, but still capable of the 5.1 playback. Anyone doing this?

I went to Microcenter and purchased three desktop PCs with i5-3570 processors at 3.40 Ghz with 8 Gb RAM, running Windows 10. Like $250 for each PC. I use them in three different secondary systems in our home for HDMI multichannel into a preamp/processor. It’s working fine with a Marantz AV7005, a Sherwood R-972 with Trinnov and an Integra unit. You might give it a try. JCR

Update. Actually the last one I bought and works fine was $130, now reduced to $99. http://www.microcenter.com/search/search_results.aspx?ntt=763763

I’m guessing here, but working on the assumption that when just using an Intel NUC as a multichannel endpoint, a NUC using core i3/5/7 processors would be overkill. So a NUC using a Celeron CPU would do. However, such a NUC is not officially supported by Roon Labs for ROCK, so it is, in effect, a MOCK device.

Appreciate the replies from @Geoff_Coupe and @Jeffrey_Robbins. However, I’m still stuck. I can’t use a full size PC as I need this multichannel endpoint to tuck away in my audio console as discreetly as a NUC would. The NUC is perfect given it has HDMI out and I believe Roon can be configured to output multichannel on that device. But, as suggested, it is expensive for this purpose.

Anyone have a less expensive option for multichannel that is small, fanless, about the size of the NUC or smaller? I plan to just route the HDMI into my AV receiver. I assume there is no way to connect a DAC in this scenario?

I put a couple of my cheap PCs underneath the respective audio cabinets and ran the HDMI cables into the cabinets so don’t necessarily give up on the PC. The ones I use are thin enough to fit laying down. JCR

Someone in another thread on HDMI audio asks if this product might work. It is cheap so you could give it a go and report back. JCR

You also asked about using a DAC. That would be USB out of one of these Windows 10 devices. Your most inexpensive options for a multichannel USB DAC would be the miniDSP U-DAC8 (which I use on my porch and have it hiding under the cabinet with the thin PC) or three of your favored two-channel DACs linked together using the miniDSP UDIO-8. I use the latter in my main system with three Musical Fidelity V-90 DACs. I just used the service from Thierry at Home Audio Fidelity (HAF) https://www.homeaudiofidelity.com to have him create custom bass management and sound correction filters for the V90 multichannel DAC, which are placed in Roon’s convolution engine. Works great and sounds way better than HDMI out of my main i7 server running Roon in the same main system, using Audyssey MultiXT32 in my Marantz AV-7702 pre/pro for bass management and sound correction. JCR

Thank you @Jeffrey_Robbins. I was the one posting in that other thread on same MC topic. I’ve concluded that sticking with Intel NUC hardware is the way to go if I want to run ROCK or Ubuntu with Roon Bridge installed. Cost was the issue of course, but found a Celeron NUC for $117. Adding RAM and SSD brings that up to $170. But still cost competitive and better than one of these mini-pcs which seem to favor Windows over Linux support. I’ll have to give up on the DAC as I just don’t want to spend a lot more money on this multichannel setup.