HOWTO: Surround sound in pulseaudio

[one51]

Args, sorry, mis-copy/paste. It is this file,

/etc/pulse/daemon.conf

Which the original Howto post describes editing.

(Yes, definitely Jaunty).

[sammydee]

Check the first post again guys, a solution is on it's way, I need to be sure it works ok for me before I write it up though. Give it a week or so, it should be up here.

Sam

[one51]

Thanks! I am happy to be a "beta tester" if you have some simple changes to try out.

Today figured out the volume control issue: have to link the main system slider to the Pulseaudio mixer (not Alsa), where the surround channels can be linked. Alsa doesn't seem to allow linking all channels, only L+R (at least in the default setup).

So what I am dealing with now, I have confirmed: some layer or hardware (NOT the sound-producing app) is rerouting channels.
* Stereo sound is (not as desired) reformatted to surround
* Subwoofer is mixed into front channels, even when playing 5.1 DVDs

Pulseaudio volume meter and mixer show that app input in stereo is converted to five channels somehow (minus sub, even though the sub works in speaker-test).

Looking forward to the fix

[sammydee]

If you are willing to "beta test" the new method, then follow these steps:

You need to add this ppa:

https://launchpad.net/~themuso/+archive/ppa

And upgrade to the latest pulseaudio/alsa. This has flat volume support as well as sound card configuration. run pavucontrol, you should see a new tab called configuration. Have a quick play with that, let me know if it works for you.

You will need to revert any changes you made to your daemon.conf or default.pa as well, this relies on HAL detecting your cards.

WARNING: I have not tested this, I have no idea how well it might or might not work. I am also not sure of whether it is possible to revert these changes properly, so please only try this method on a non-critical system.

I'd appreciate feedback on this, positive or negative.

Sam

[one51]

Hi Sam, I completed my backup and tried this out today. Nothing catastrophically bad, but I noticed a few things:

1) Config section of the PulseAudio volume control GUI can set 5.1 surround, but it reverts to 2-ch on logout/login or on restart
2) When the Rhythmbox track changes to the next mp3, the volume of the PulseAudio mixer sometimes gets adjusted (!), happens more frequently when volume of the track is high
3) Volume slider on taskbar no longer actually controls anything (even if I have "Sound" preferences set to PulseAudio playback mixer, which fixed my previous problem with this slider). So before I had a config error (between chair and keyboard), but this time I think it's Pulseaudio or something.
4) A problem that I also had before this upgrade that didn't go away: at very low (but non-zero) volume settings, there is a loud static noise that suddenly appears. Something must be interfering at low volume levels, perhaps a noise filter of some kind?

I changed my daemon.conf back to the old one (with channels = 6 hard set) and then it at least solved problem 1) on re-login. But it shows that something is not correctly detecting, and the manual config in the GUI is not being saved.

Most annoying: even though speaker-test still works (sound outputs properly from the correct 6 speakers): LFE still doesn't output anything when I run applications, stereo tracks are still remixed to surround, and I'm not convinced that 5.1 is even playing correctly on the 5 (minus 1) channels. I suspect it's also a stereo signal that is being remixed to "false" surround (echo added, and equal signals in L+R sent to Center).

My guess is that my sound chip, the Via 1708S (not listed as supported on Alsa website?) is being interpreted as another VIA chip and isn't getting the correct configuration. The chip and/or some software layer is remixing things in a wrong way. How can I report this bug or request this functionality? (longtime computer geek, new to Linux, because such problems as this put me off Linux for the last 6 years).

[arbrandes]

Instead of using themuso's PPA, I'm going to give a shot to this other one, which has Hardy packages:

http://ubuntuforums.org/showthread.php?t=789578

Funny thing, the problem I'm having with libasound 1.0.15 is a recognized bug in Hardy, version 1.0.16 actually got uploaded to -proposed, but later deleted due to regressions:

https://bugs.launchpad.net/ubuntu/+s...io/+bug/221673

Wish me luck!

Adolfo

[arbrandes]

Ok, everything went smoothly with psyke's PPA. Still had to change daemon.conf according to this howto, but now basically everything works, especially my personal holy grail (which I hadn't achieved as of yet):

1) Upmixing stereo sources automatically and transparently...

2) ... while playing 5.1 sources normally,

3) all the while with an Alsa-compatible master volume control for all channels.

Only glitch left is with MythTV, which for some godforsaken reason cannot control the volume. Probably something to do with the fact that until a few days ago the svn version wouldn't work with pulseaudio at all!

Adolfo

[ceylonerana]

Thank you for your great post. I have one thing to ask from you. I use Kubuntu Intrepid. But there is no daemon.conf file to edit. It has client.conf file. So how can I go through that
Thanks....

[mikeize]

Thank you Arbrandes! I too have made progress with the method you describe. The only thing wrong now, is that both rear channels are getting mixed together as "rear lfe". That is, neither rear left or rear right works during the speaker test, but they seem to both work during the "rear lfe" test. Still, this development gives me hope!

-mike

[one51]

After PulseAudio started giving me occasional dropouts (pops and crackles), starting after I tried the PPA and then (painfully) deinstalled it... I decided to disable PulseAudio. Alsa is still able to play multiple sources at once, and do surround (when I manually select correct audio stream in VLC or MPlayer). Even found a method to properly play stereo PCM sound on L+R speakers.

If PulseAudio improves so that there aren't so many 100+reply threads of people with problems, I'll try it again on Ubuntu "Sprightly Sparrow" or whenever that occurs. Good luck to all...

Now if only I could get SPDIF to work properly on my VT1708S.