USB Sound card with surround over optical?

[druck]

Hi,

Does anyone know of a USB sound card compatible with the Raspberry Pi
(i.e. Linux) which can do 5.1 surround sound over S/PDIF?

The reason being I've got an old Blu-ray surround sound system which I'm
no longer using with the TV and fancy using as computer speakers
instead. The only way of driving it is via optical, and all the cheap
USB sound cards I've looked at, such as Star Tech, say optical is
limited to stereo PCM.

I'm after a cheap solution, as if it's more than a reasonable set of 2.1
computer speakers, I may as well ditch the old system as its bulk and
overkill for the small room.

---druck

[Andy Burns]

druck wrote:

> Does anyone know of a USB sound card compatible with the Raspberry Pi
> (i.e. Linux) which can do 5.1 surround sound over S/PDIF?

You can't do true 5.1 over S/PDIF, so you'd need a USB device that could
encode to compressed DTS or AC3

> I'm after a cheap solution

I think you'll struggle, just maybe something like this? Double-check
it can do what you want ...

<https://us.creative.com/p/sound-cards/sound-blaster-x-fi-surround-5-1-pro>

[Chris Elvidge]

I use one of these (well a similar item)

https://www.ebay.co.uk/itm/384079002059?hash=item596ce479cb:g:q2IAAOSw1g1fZJJ~

HDMI repeater with S/PDIF and/or RCA sound extraction

--
Chris Elvidge
England

[Adrian Caspersz]

On 22/04/2021 16:50, druck wrote:
> Hi,
>
> Does anyone know of a USB sound card compatible with the Raspberry Pi
> (i.e. Linux) which can do 5.1 surround sound over S/PDIF?
>

There is an "A52" ALSA plugin to allow surround encoded files to play.

https://help.ubuntu.com/community/DigitalAC-3Pulseaudio

Been a long while since I fiddled with it.


Does your blueray speaker set have HDMI and hence some sort of audio
return channel support?

--
Adrian C

[The Natural Philosopher]

On 22/04/2021 16:50, druck wrote:

A better solution IMHO is to query your assumptions - why on earth use
USB? You have HDMI sound already so...

https://www.amazon.co.uk/Converter-Optical-Toslink-Extractor-HD-1080P-Black/dp/B016XMDKXC


will give you 5 channel optical sound from that, allegedly...

--
"A point of view can be a dangerous luxury when substituted for insight
and understanding".

Marshall McLuhan

[druck]

The old surround sound system is from 2009 so doesn't support HDMI arc,
only optical in from the old TV of the same vintage.

However thanks for the link above, as that may help me get the Pi in the
living room to do surround sound with the new TV/soundbar. So far I've
not managed to get the Pi to do anything other than stereo.

The Linux laptop with an nVidia card had a bit more luck with that
setup, the 5.1 and 7.1 devices worked albeit with the centre and
subwoofer swapped. When I tried to reconfigure that, I lost sound
completely and had to wind back the configuration.

---druck

[druck]

On 23/04/2021 09:42, The Natural Philosopher wrote:
> On 22/04/2021 16:50, druck wrote:
>> Does anyone know of a USB sound card compatible with the Raspberry Pi
>> (i.e. Linux) which can do 5.1 surround sound over S/PDIF?

> A better solution IMHO is to query your assumptions - why on earth use
> USB? You have HDMI sound already so...

> https://www.amazon.co.uk/Converter-Optical-Toslink-Extractor-HD-1080P-Black/dp/B016XMDKXC

Thanks for that, it may be worth trying if I can get another Raspberry
Pi to do 5.1 or 7.1 over HDMI to the new 9.4.1 soundbar, so far only its
only wanted to stereo.

---druck

[druck]

On 22/04/2021 17:13, Andy Burns wrote:
> druck wrote:
>
>> Does anyone know of a USB sound card compatible with the Raspberry Pi
>> (i.e. Linux) which can do 5.1 surround sound over S/PDIF?
>
> You can't do true 5.1 over S/PDIF, so you'd need a USB device that could
> encode to compressed DTS or AC3

That's useful to know, explains why the cheap ones don't do it.

>> I'm after a cheap solution
>
> I think you'll struggle, just maybe something like this?  Double-check
> it can do what you want ...
>
> <https://us.creative.com/p/sound-cards/sound-blaster-x-fi-surround-5-1-pro>

Yes, I could get a fairly decent set of speakers for that.

---druck

[druck]

On 22/04/2021 17:37, Chris Elvidge wrote:
> On 22/04/2021 04:50 pm, druck wrote:
>> Hi,
>>
>> Does anyone know of a USB sound card compatible with the Raspberry Pi
>> (i.e. Linux) which can do 5.1 surround sound over S/PDIF?

> I use one of these (well a similar item)
>
> https://www.ebay.co.uk/itm/384079002059?hash=item596ce479cb:g:q2IAAOSw1g1fZJJ~
>
> HDMI repeater with S/PDIF and/or RCA sound extraction
>

Does it do 5.1 on the optical though? The description seems to suggest 2
channel PCM on SPDIF or nothing.

---druck

[Theo]

Also in cheapass ebay version:
https://www.ebay.co.uk/itm/144016586207
(I think it's the same thing, just a photo rather than a render)

If you're on a Pi 4, I wonder if you could use the second HDMI port just for
audio?

Theo

[Chris Elvidge]

I only use it through a stereo system.
However, the HDMI to the TV, and then optical out to a 5.1 DVD player
digital aux input is OK. I'll try it and let you know.

--
Chris Elvidge
England

[Chris Elvidge]

On 23/04/2021 08:23 pm, druck wrote:

If the HDMI digital is 5.1, why shouldn't the digital optical be 5.1 too?
The RCA outputs have been run through a D/A converter, so stereo.

--
Chris Elvidge
England

[Scott Alfter]

In article <iedll5...@mid.individual.net>,

Andy Burns <use...@andyburns.uk> wrote:
>druck wrote:
>
>> Does anyone know of a USB sound card compatible with the Raspberry Pi
>> (i.e. Linux) which can do 5.1 surround sound over S/PDIF?
>
>You can't do true 5.1 over S/PDIF, so you'd need a USB device that could
>encode to compressed DTS or AC3

If by "true 5.1" you mean multichannel PCM audio, that's correct, but if
your sources are DTS or AC3 audio under ~1.5 Mbps (AC3 maxes out at 640 kbps
IIRC) or if you have some means to transcode on-the-fly, you can pass
multichannel audio over S/PDIF just fine. I did that for years with a
MythTV frontend into an older receiver. Cheap soundcards worked just fine,
so long as they had S/PDIF output.

Come to think of it, for a while I think I was using a USB S/PDIF adapter
instead of a soundcard. I don't recall having to look for anything in
particular; USB sound devices of all sorts tend to work without problems
with Linux.

_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( https://alfter.us/ Top-posting!
\_^_/ >What's the most annoying thing on Usenet?

[druck]

On 26/04/2021 23:17, Scott Alfter wrote:
> In article <iedll5...@mid.individual.net>, Andy Burns
> <use...@andyburns.uk> wrote:
>> druck wrote:
>>
>>> Does anyone know of a USB sound card compatible with the
>>> Raspberry Pi (i.e. Linux) which can do 5.1 surround sound over
>>> S/PDIF?
>>
>> You can't do true 5.1 over S/PDIF, so you'd need a USB device that
>> could encode to compressed DTS or AC3
>
> If by "true 5.1" you mean multichannel PCM audio, that's correct, but
> if your sources are DTS or AC3 audio under ~1.5 Mbps (AC3 maxes out
> at 640 kbps> IIRC) or if you have some means to transcode on-the-fly,
> you can pass multichannel audio over S/PDIF just fine. I did that
> for years with a MythTV frontend into an older receiver. Cheap
> soundcards worked just fine, so long as they had S/PDIF output.

I don't know if playing DTS or AC3 audio on the Pi connected to the new
surround system via HDMI is being sent in that form over HDMI, it
certainly isn't sound as if it is.

Multichannel PCM isn't working as no amount of setting up ALSA or
PulseAudio is giving anything other than a 2 channel down mix when using
speakertest, regardless of the device.

> Come to think of it, for a while I think I was using a USB S/PDIF
> adapter instead of a soundcard. I don't recall having to look for
> anything in particular; USB sound devices of all sorts tend to work
> without problems with Linux.

I first need Pi's internal HDMI output to do 5.1, before I can think
about using SPDIF for the old sound system.

It's looking like far more effort than it is worth.

---druck