[V4L] problem with a TV card

Hi. I have a TV card model maxi TV video pci 2 from guillemot.
If I see the tv, I do

modprobe -v bttv pll=1 card=14 radio=0
modprobe -v i2c scan=1
modprobe -v tuner type=0

All is OK. That is, I see the TV with the xawtv program but I can't hear

the TV.
Somebody knows what I can do to hear the TV?

I have the Red Hat 7.0 distribution with kernel 2.2.17

Thanks a lot,

Arnau.