[PlanetCCRMA] Crackling sound - ATI Rage Fury Pro?

Mark Knecht markknecht@gmail.com
Wed Aug 24 13:56:02 2005

On 8/24/05, mArukqs <marukas@hardcore.lt> wrote:
> Hello,
> sometimes I get crackling sound when working with jack application (f.e.
> Ardour, Hydrogen) - sometimes it occurs while scrolling the web page in
> Mozilla, but sometimes it occurs when no browsers are open.
> My configuration is AMD Athlon +3000, ATI Rage Fury Pro, M-Audio
> Audiophile 2496, NVidia motherboard, 512 RAM, 7200rpm disks on reiserfs,
> Fedora Core 2 with latest CCRMA applications.
> All the requirements from ardour.org are met. What can be faulty? Is it
> the problem of my ATI card?

I'm going to guess that it's a combination of things. I have a very
similar problem with my HDSP 9652 and OSS emulation in Alsa. It
produces many problems like you describe. With hdspconf (an HDSP
specific tool) I can see that OSS is trying to change the frequency of
the card on the fly based on what frequency some web material is
recorded at. All sorts of material is different, I guess, so I get
lots of attempts at sample rate changes and lots of crackling.

OSS emulation on the HDSP 9652 is basically all messed up in another
way also. This card has 26 outputs. OSS takes a stereo signal and
places it on all 13 pairs. These 13 pairs are then summed. The summed
signal is too strong creating overs and distortion. What a mess.

I've found that (for me) the best comprimise is to always be running
Jack. If I start Jack when I first log into the system then stuff
mostly works. When it doesn't it doesn't, but at least I don't have
clicks and pops and crackles and all that stuff. Sometime stuff
doesn't work though and this just seems to be a problem with Alsa.
Possibly that could be handled with some sort of virtual device but it
hasn't been important enough to me to worrry about.

Don't know if any of this was helpful. Good luck figuring it out on your end.