[SOLVED] Re: speaker-test: no correct sound output on LFE and others speakers

[Franco Martelli <martellif67@gmail.com>]

On 30/04/24 at 14:07, Alexandre Rossi wrote:
> Hi,
>
> > Basically I've the same issue described here:
> > https://askubuntu.com/questions/1180389/speaker-test-returns-all-6-channels-to-front-speakers
> >
> > The speaker-test program is provided by the alsa-utils package. I'm using
> > Debian 12 Bookworm, I've no ~/.asoundrc file. My /proc/asound/cards returns:
> >
> > ~$ cat /proc/asound/cards
> >   0 [SB             ]: HDA-Intel - HDA ATI SB
> >                        HDA ATI SB at 0xfe400000 irq 16
> >   1 [NVidia         ]: HDA-Intel - HDA NVidia
> >                        HDA NVidia at 0xfe080000 irq 57
> >
> > I've 5.1 speakers the LOGITECH Z906 audio system plugged to the PC via 3
> > jacks (left/right), (Center/Subwoofer), (Rear left/ Rear right).
>
> I assume your cabling is right and your SB soundcard has surround out
> (3 jacks as you describe it, and not mic and line out for instance). The labels
> on the jacks would confirm that, so would the user manual of your motherboard or
> sound card.
>
> > The issue is that speaker-test doesn't play sound to the correct speaker. If
> > I run:
> >
> > ~$ speaker-test -Dplug:surround51 -c6 -s3 -f75
> >
> > The sound comes from (Center), (Front right), (Rear left) and (Rear right)
> > speakers instead (Front right) only.
>
> What's bothering me is that you get sound from multiple speakers while
> instructing out on only one.
>
> The usual issues of these setups with surround analog out are:
> - channel mapping issues (driver/hardware mismatch)
> - software downmixing to stereo
>
> There are other usual issues with surrount digital out but this is not
> your setup.
>
> You can have a look at [1] for software fixes on this.
>
> [1] https://alsa.opensrc.org/SurroundSound

I solved by buying a Toslink (S/PDIF) optical cable, and using thus the 
"Surround 5.1 Digital output" and unplugging the three jacks analog 
cable. Now speaker-test works nicely:

~$ speaker-test -c6 -l1 -twav

speaker-test 1.2.8

Playback device is default
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 32 to 349525
Period size range from 10 to 116509
Using max buffer size 349524
Periods = 4
was set period_size = 87381
was set buffer_size = 349524
 0 - Front Left
 4 - Center
 1 - Front Right
 3 - Rear Right
 2 - Rear Left
 5 - LFE
Time per period = 8,720806

maybe it was a hardware issue with the DAC of my Logitech Z906, it seems 
that with the three jacks analog cable it downmix to stereo, thanks anyway.

Cheers,
--
Franco Martelli