How to disable 'dmix' for Terratec DMX 6Fire (ice1712)?

Hi!

I have a Terratec DMX 6Fire (ice1712 chipset) card, unfortunately the
sound is very choppy (in Banshee) and often the sound stream stops.

From previous experience I know that the card works fine without alsa
'dmix' and thus I would like to disable it.

I've tried to add the following line to .asoundrc:

pcm.!default "plughw"

as suggested by

https://bugzilla.novell.com/show_bug.cgi?id=114745

But the sound still crackles a lot.

Anyone have any idea?

/Thomas