ALSA surround center speaker problems
 

I have a CMedia 8738 (supported by ALSA), and Im using a Surround 5.1 speaker set from creative with it. Everything is fine hardware-wise, connections are in the right place, etc. All my speakers work, except for the center one. Ive done some searching, tried numerous things (like recompiling ALSA with different options, etc.), and none seem to work. However, I did pick up a little info. In the alsamixer, there should be some options called Surround, Center, and Wave that should be turned on. I dont seem to have that in mine. All the ones this has are these (output of amixer scontrols):
Does anyone have any ideas?

could you try this:

amixer set Center 100

and tell us what you get?

It says its unable to find that control. Is there any way to add that control?

Alsa does not think it has such a capability. . .

Have you used this sound card (on-board I am guessing) with full 5.1 before?

if your center is not working then your LFE (subwoofer) channel is out too... can you confirm this?
(note that 5.1 speakers (when connected through the subwoofer will offload low tones to the subwoofer by default. But the subwoofer can't go to loud. If it gets a direct LFE signal it can be a lot louder)

Which version of ALSA are you using?
Some of the drivers are different between the alsa packages for 2.4 and the 2.6 kernel version of alsa. (my audigy for example, sounds like shit with 2.4 and alsa vs. 2.6 with built in alsa (much better. It's a driver issue with hardware mixing.)

I use ALSA 1.0.5, which I compiled myself (the driver is in 1.0.5a, so I use that. Whats that about hardware mixing?). I havent used this soundcard with any speakers before except 2 older speakers. I have a Mic As Center/LFE option, but nothing else mentioning Center or LFE, although my subwoofer DOES work.

is the 'mic as center/lfe' switch on?

No, I have that turned off, since I have a free Mic socket in the back of my soundcard.

PS: I forgot to mention that the card is onboard, but has the same capabilities (like 6 channel sound, ALSA has a swtich for 4 channel sound, but no 6 channel...)

Wait. You have it turned off?

How many cables do you have connected to your sound card?
1= 2.1 channel and 2 channel.
2= 4.1 channel and 4 channel.
3= 5.1 channel.

One plug is for front left and right.
One is for back left and right.
One is for center/lfe.

You need all three to get full 5.1 channel sound.
You also need to turn that on.

I have 3 cables connected, so hardware-wise Im ready for 5.1. Ill try turning on that option and tell you what happens.

Just turned the option on. Nothing out of the center speaker still. Anything else I can do? Maybe theres a way to turn those Surround/Center options on...

Ok now that it is on... stick the center/lfe cable in the mike jack.

Oh, ok. Ill try that...

Nope, still nothing from the center.

Well I give...

only so much you can do over the net.

Good luck.

EDIT:
One last thing... have you checked alsamixer now for a new mixer to set now that you have turned the mic-to-center/lfe on?

You mean check that alsamixer actually did its job with setting that option to on? I have gnome-alsamixer, and it confirms that its on. Oh well. Thanks for the help, Ill keep searching. And when I find a solution, Ill post a mini-howto :D!

The reason you are not getting center is because the sound source needs to have multiple channels recorded. Almost all the music today is stereo, so you would not be able to play on all 5 speakers or surround sound. I think your speakers that you have is detecting stereo only so it sent the sound to four channels and it also mixed the two channels for the subwoofer. To make sure your setup can play 5.1. Download speaker-test from the ALSA wiki site. If all channels works, run mplayer but in the command line add "-channels 6 -ao alsa1x:surround51". Next play a DVD movie or an AVI movie with AC-3 audio. You should be able to hear in 5.1 surround sound. Though in the movie, try to pick a scene where a lot is going on. If mplayer complains that it cannot find surround51. At the console type "aplay -L". You should see a whole list of entries you can use. Usually surround51 should be in the list.

Not all motherboard manufactures programs the sound chip the same, so the ALSA module may not work well in 5.1 set ups. You may have to use digital output or get a real sound card.

I have surround51 in aplay -L. I ran the speaker-test program, and something odd happened. To speaker-test, the test was successful. But I heard the Front Left and Center speakers were the same, i.e., when it played center, the sound came out of front left. Its not just music that I try, its some games, too, like Max Payne 2 or Warcraft3.

EDIT: How would I enable digital output? Alsamixer doesnt have an digital output options in it. Maybe theres a way to put options in alsamixer?

That's a good point ( and the first good point I have read from Electro at that). . .

Some on-board sound chips don't down mix 2 channel audio playback into 5.1 channel sound.

My on-board sound does this in fact. But I use an Audigy now... god I love that card.

You should consider getting a "real" sound card. The difference in sound quality is amazing.

Do your speakers support digital input? if not you are wasting your time thinking about it.

Thanks for the input guys. I think Ill just order an SB Live! and get some real sound quality :D (although there isnt an option to disable onboard sound in the BIOS...).

Get Turtle Beach Santa Cruz. It has a lot better sound quality than Creative Soundblaster LIVE and Audigy. It does not color the sound like Creative Labs cards do. I have a Turtle Beach Santa Cruz. The sound is a lot better.

Look in your motherboard manual for a jumper setting.

Thanks for the opinion, but my friend has an Audigy and when I listened to it, I LOVED it :D. Ill look at the mobo manual, thanks.

The Audigy is a much better investment then the LIVE 5.1.

It is fully supported under linux and sounds great.

Turtle Beach Santa Cruz is over priced. . . you can pick up an OEM Audigy for under 60 bucks Canadian. And IMO they sound almost the same (to me the Audigy sounded better and adds firewire to your system)

The Santa Cruz is not over priced. I payed about $43 for it at newegg. In LINUX, there is no support for 96 KHz sampling rate, 24-bit resolution, and EAX. Creative Labs sound cards killed several of my systems by corrupting data. Search this forum, you will found out that people said that the Santa Cruz is much better than Audigy 2.

I guess people are too brain washed over the years when Soundblaster LIVE! came out.

Have a look at http://www.pcavtech.com/soundcards/compare/index.htm

I never said Audigy 2. . . I said Audigy and Audigy OEM. . . Different stories compleatly.

And BTW that link is very dated. . .