Digital Stereo Duplex sound on an optical 5.1 output..

**Yionel** · May 11th, 2010

Hi everybody,

Sorry I'm french so I have to explain my problem simply.
I have an optical output connected to an ampli but this output is always in stereo.
My pc is a notbook Acer 7730G and it's specified :

True5.1-channel surround sound output
High-definition audio support
S/PDIF (Sony/Philips Digital Interface) support for digital
speakers

But under Ubuntu I have digital stereo duplex

Of course, I would have surround effect !
I think it's about passthrought option but I don't know where I can modified it.

Code:

$ lspci | grep -i audio
00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)

Code:

[yo@yo-laptop:~] $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC888 Analog [ALC888 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 1: ALC888 Digital [ALC888 Digital]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 3: NVIDIA HDMI [NVIDIA HDMI]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Code:

[yo@yo-laptop:~] $ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=Intel
    HDA Intel, ALC888 Analog
    Default Audio Device
front:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    Front speakers
surround40:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Intel,DEV=0
    HDA Intel, ALC888 Digital
    IEC958 (S/PDIF) Digital Audio Output
hdmi:CARD=Intel,DEV=0
    HDA Intel, NVIDIA HDMI
    HDMI Audio Output

Can you help me ?
Thanks a lot !!

**Yionel** · May 13th, 2010

Nobody for my problem ?

**isledur** · May 16th, 2010

Same problem - no good leads

**Yionel** · May 16th, 2010

I have found the solution \o/

http://www.yionel.com/?p=297

It's my blog, sorry it's in french

**neilfeld** · May 27th, 2010

Hello,

I have encountered the same issue and your webpage is not loading. Can please post your findings?

Merci

**Yionel** · May 27th, 2010

Yes of course. I'm stupid because the page can't be loaded now because my server is out !

So you had to : check is system > preference > sound > hardware > Analog Stereo Duplex

After, with command alsamixer : demute (m) spdif output

And in the software like VLC
-> use SPDIF when avalaible
-> output module : ALSA audio output
-> ALSA : check the good output optical (HDA Intel : ALC888 Digital (hw:0,1) for exemple