.. TV , DVD , recording are OK.
But when I'm listening to music, the sound is not clear, is crackling, almost the same effect as a bad FM radio signal. All my music has been ripped with MythMusic in mp3, not ogg, in high level.
The sound was OK before.

Any idea ?

I'm using KnoppMyth R5A30.1
The sound card is built-in sound card of my motherboard. (GA-7VAXP ,
yes it's a VIA chipset, but I got no problem so far. I can record a program and look at it in the same time and look another recording on another computer in the same time).

You might try and see if this is related to the TV or to the actual sound being produced by the system.

Plug in a set of headphones (if possible) or run it out to a stereo.

In addition, try dropping the output from the system if the alsa volume is cranked to 100%.

just a thought or two..

L0o0ky

my system is plugged on an amplifier. No sound through the TV.
As I said before, the sound is great when I watch TV or a DVD with mythTV.

I will look at the ALSA volume. Maybe it can help.

Does the crackling sound change or diminish if you hit "4" and go to a full screen visuallization?

Nothing changed in full screen.
ALSA volume was not at 100 %

OK, so it's not interference from the videocard or TV. What other sources of RF noise do you have nearby? The key to is to go through eliminating whatever you can (for example turning off the TV, unplugging the network cable, ...) and determine the source. Once you do that, you can take steps to correct it. It might also be something as simple as a loose connector or a dirty volume control.

Ok,

To sum up my understanding of the problem:
The knoppmyth system does not have this sound problem while watching TV or DVD's.
You aren't maxing out the gain on the sound card volume etc...

One thought though.
You mentioned you had ripped these files with MythMusic. Have you tested these files on another machine?

Is it possible that the crackling sound is actually in the MP3? Have you tried ripping a song in a lower quality mode? (just to see if there is a difference.

If you were to have an issue with jitter during the rip, you might end up with odd sound issues. Testing them on another machine might help eliminate another possible cause. As EvilTwin said, eliminate whatever you can.

L0o0ky

It's what I was wondering. Maybe the quality of the MP3. I'm using high level encoding. Ogg format is too big for my use. I'm gonna try on another computer.

It's strange , this morning, the sound seemed to be correct.
I'd like to enable my digital spdif to see if there is a difference. But the HowTo is for NForce2.

I have a similar problem. It drove me mad for months. It was always at the same location in an MP3 file, so I assumed that it was an encoding bug ... except that the same file played back perfectly on my Mac (where it was ripped).

I eventually found that turning the volume down to about 70% was necessary. (I think volume down is bound to square left bracket)

No idea why I couldn't hear it in TV recordings, but I assume the distortion is either caused by an audio driver bug, or that it is clipping on the audio outputs.

This is on a cheap Gigabyte GA-7VM400AM motherboard.

_________________
| Nigel Pearson, nigel.pearson.au@gmail.com
| "Things you own end up owning you" - Tyler, Fight Club