Glass sounds on playback

I have a problem with Ardour. Thank’s to UbuntuStudio Karmic’s new low-latency kernel I can gain good results with recording.
My only problem is, when I want to playback the tracks, the playback is noisy. It’s like I’d listen to the sounds through glasses. What can cause the problem? I have no xruns so far, but from time to time the sound starts to become distorted.

Audigy 2
1.5 GB RAM
Intel Celeron-D 2.66 GHz

You have a Soundblaster. Case closed.

Well maybe not definitly, but most likely the noises will disappear if you run it at 48kHz instead of 44.1.
Most of the SB’s do an internal resample to 48kHz and that’s probably what causes the noise.