Sound only from Left Channel??? (Solved....with a workaround)

[headholio]

I have a T6412 motherboard which I think has AC '97 Audio, Dolby 5.1 (6-channel) onboard sound. My problem is that I can only hear sound from one of the two speakers. At first I thought it was the speakers but after swapping them for a backup set I realized that it's Kubuntu. I checked Kmix to see if the slider was set to left channel only, but Kmix no longer has the slider bar for left and right channels. That seemed odd to me, so I loaded up Alsamixer, and everything seems to be ok, but again in Alsamixer I don't see any options to adjust left and right channels. Just volume sliders for each type of output. Lastly, I loaded up aumix, now this program showed me the balance sliders for left vs right channels, and I am able to adjust them, however, when I slide it all the way to the right, I get no sound at all. If I slide it to the middle or left, then I can hear only the left channel.

Is there something else I should check

[dibl]

Re: Sound only from Left Channel

I think you're in contention for "weirdest problem of the day" award!

You have a classical troubleshooting problem here -- you gotta start narrowing it down to something specific. I'd try something like this:

1. Does the problem happen in this OS only, or any OS? Boot a Live CD (any Live CD) and test the sound. If it works perfectly, the problem is Kubuntu-related. If it's left channel only, with any OS, it's a hardware problem.

2. If it's a hardware problem (which I would suspect), then there's a daisy chain of suspects, starting with the connections where the speakers plug in, and then the motherboard connectors, and the chip itself.

3. If it's Kubuntu, then I'd say it's mixer-related, most likely -- mainly because your description sounds like Kmix is broken. Try re-installing kmix, for starters.

HTH!

[quarkslot]

Re: Sound only from Left Channel

I absolutely love this sort of problem, but only after I've fixed it, for the moment you are in for a rough ride.

As dibl says you have to do some diagnostics to narrow it down.

Unless I have misread you do you know for a fact that the on-board sound was working in the first place, are you sure this isn't a hardware problem i.e. the motherboard is only kicking out on the left channel?

[Zorael]

Re: Sound only from Left Channel

This isn't as unusual a problem as one might hope. Have a look at http://ubuntuforums.org/showpost.php?p=5017453 and see if anything there applies.

[toad]

Re: Sound only from Left Channel

It happens to me periodically because of my cat playing with the cables. Make sure the lead is plugged in properly

[headholio]

Re: Sound only from Left Channel

First, thanks for the suggestions guys. They actually helped steer me in the right direction.

A little info for everyone....I just bought this motherboard used since my old one died, and I just finished putting my rig together. I am new to this motherboard/processor so I can't vouch for it's audio port working in the past. The previous owner said that the board worked great, but it is possible that he might have held back information about the rear port not working properly.

So anyways, here are my troubleshooting efforts...... I booted from the Kubuntu Live CD and there was not sound from the right channel with that either. So then I checked the front panel audio and plugged my speakers into that port instead. Low and behold, I had both channels! So then I tried disconnecting the front panel audio lead from my motherboard, and this left me with no audio at all. Then I checked the manual for my motherboard and it said to jumper two sets of pins together if I'm not going to use front panel audio, so I did that, and was once again left with the rear port working, but only for the left channel. So I'm going to assume that the motherboard has a problem with it's rear audio port.

So my solution in the mean time is to plug my speakers into the front panel audio port instead. If I get tired of that setup, then maybe I'll just throw my SB Live card into the system. But for now, I guess I'll stick with the wire in front.

Thanks again everyone, if you have any more suggestions, feel free to lay them on me.

[Zorael]

Re: Sound only from Left Channel

Awesome.

Do note, though, that depending on the model= argument passed to the driver (as detailed in the post I linked towards), it uses different methods of jack sensitivity, so unless it's a hardware issue you may be able to fix it with a bit of software tweaking. I only get sound on one speaker on my Acer laptop until I manually add model=acer, after which everything works nicely. Supposedly (?) the ALSA modules in the kernel are somehow old, ergo many if not most problems can be worked around by simply compiling new and fresh ones.

[toad]

Re: Sound only from Left Channel

Well done, no point blaming the cat then.

Could I ask you to mark the thread as SOLVED please. Info in my signature.

Thanks!

[headholio]

Re: Sound only from Left Channel

Zorael: I checked your thread, and saw that the Module I'm using in Alsa is atiixp.sn and in the file you mentioned, there are no different models for the particular module. So I couldn't pass any special module criteria as you recommended. I'll mark this as solved, but feel free to recommend any other software checks if you have any. I'll try them all.

[toad]

Re: Sound only from Left Channel (Solved....with a workaround)

Yeah, and if it isn't properly solved then do not let me goad you into marking it as solved

[dibl]

Re: Sound only from Left Channel (Solved....with a workaround)

It probably is "just hardware", but to make certain, I would run

lspci

and see the exact chip model, and then check on the ALSA project site to see what the correct driver for it is. Here's the link:

http://www.alsa-project.org/main/index.php/Matrix:Main

Then do a Google search on the correct driver, to see if there are any options or switches that you can use with it.

[headholio]

Re: Sound only from Left Channel (Solved....with a workaround)

Well, this is the relevant output from lspci "00:14.5 Multimedia audio controller: ATI Technologies Inc IXP SB400 AC'97 Audio Controller (rev 02)" and the alsa module for this is snd-atiixp (which appears to be loaded properly). I searched google for info on snd-atiixp and came up with nothing. So I would assume it's safe to say it's a hardware problem

[dibl]

Re: Sound only from Left Channel (Solved....with a workaround)

So I would assume it's safe to say it's a hardware problem

Yep.

The fact that it works when connected to the front panel really gives it away. Here's what I suspect: If you look very closely (with magnification, perhaps) at the connecting pin on your speaker wire, you will observe that it has two parts, which are separated by a very thin insulator. One part is left channel, the other right. Inside the jack, there is a pair of springy friction points designed to press against the two parts of the pin, thus connecting both channels. The jack on the back of your PC is worn, or got stressed (somebody pulled sideways on the speaker wire) and the springy piece for the left channel got bent away from its normal position. So, when you push in the pin, it isn't touching and making the connection. Probably it is the innermost/deepest pair of contacts in the jack.

A real enterprising soul, armed with a dental pick and lots of light on the work, could probably pull the springy piece inside the jack back into position. With the computer disconnected from electric, of course.