System Whine/Mouse Noise Through Speakers

[Bezmotivnik]

[v9.04]

C-Media CMI 8738 [Ubuntu-identified]

Good board, but when I hook up speakers to the MB's audio line out, they have a constant high-pitched whine and various system racket coming through the speakers -- mouse growl when rolled, drives racket, etc.

Music and sound comes out, but this racket makes listening unpleasant.

Any thoughts on this? Drivers, board defects, what?

As always, thanks for any help.

00:05.0 Multimedia audio controller: C-Media Electronics Inc CM8738 (rev 10)
Subsystem: ASUSTeK Computer Inc. Device 80e2
Flags: bus master, stepping, medium devsel, latency 32, IRQ 10
I/O ports at a400 [size=256]
Capabilities: <access denied>
Kernel driver in use: C-Media PCI

[xc3RnbFO8P]

Maybe the Jack?
Did you try headphones?

[Bezmotivnik]

Maybe the Jack?

No, that wouldn't explain the symptoms, but I checked anyway. It seems fine.

Did you try headphones?

Yeah, identical noise problem from that output jack.

[xc3RnbFO8P]

It could be wrong type of Jack:
http://en.wikipedia.org/wiki/TRS_connector

[Bezmotivnik]

It could be wrong type of Jack:

No, it's fine.

The stereo output works and I get sound -- I just get all this other system noise, too.

I went into alsamixer and boosted the gain, which helped the S/N ratio, but the noise is still unchanged -- just less in the overall signal.

[eldragon]

theres nothing you can do about it...its intereference, probably due to bad design of the hardware....(mainboard, or sound subsystem).

maybe...and its a BIG maybe, replacing the PSU would help.

[madnessjack]

I've had this a fair bit, it could be to do with a noisy motherboard or psu.

I fixed it by unplugging nearby electrical appliances. If you're connected through an extension cable this could also be noisy. I think the noise was still there but it wasn't nearly as bad as it was, and I was able to record with a very acceptable s/n ratio.

[Bezmotivnik]

I've had this a fair bit, it could be to do with a noisy motherboard or psu.

How could a PSU possibly cause mouse and hard drive noise?

Bad board design, yeah, though this is pretty extreme for a high-end (if old) ASUS momboard.

I fixed it by unplugging nearby electrical appliances. If you're connected through an extension cable this could also be noisy. I think the noise was still there but it wasn't nearly as bad as it was, and I was able to record with a very acceptable s/n ratio.

Again, I don't see how this could produce mouse and drive noise.

External noise sources aren't the problem here; it's a clean AC line that's running through several filters in my (non-Linux) recording studio.

[madnessjack]

Because sound gets converted from electricity, so any interference will affect it

[igorzwx]

"00:05.0 Multimedia audio controller: C-Media Electronics Inc CM8738 (rev 10)"

Is it yours?
23 oss_cmpci pci13f6,111 CMedia CM8738/CM8768
http://mercurial.opensound.com/?file...devlists/Linux

It might be interesting to try another sound system and
see if it produces noise too.

Another Ubuntu 9.04 in dual boot,
and install OSS4
https://help.ubuntu.com/community/OpenSound