No AC3 Sound on 1981b Audio HP Dc7100

[CPT_MAC]

Hi,

 

maybe some one give me some advice or point me in the right direction?

 

Hardware HP's DC7100 ICH6 Intel on bord sound 1981b, sata HD Sata DVD, grphic Nividia 8400gs PCIe

 

Software Ideneb 1.6 Osx 10.5.8

 

Generali every thing works.

 

Sound with 1981 SPIDIF digital out too!

 

I can not select in midi setup AC3, only stere 2 channel.

 

When I open any Movie with AC3 sound all programs crash! (VLC, boxee, DVD-Player).

 

I have to restart than the computer to get digital PCM sound back.

 

Is there a basic problem, that 1981b does not support AC3 at all? I could not find any information about so far.

 

I installed a PCI sound card with CMI8738 sound chip and optical SIDIF which may should do the job.

 

My problem now is, I can not disable on board sound in HP's BIOS. I can only deactivate the interrupt. Disable the interrupt results in no audio at all and with enable of interrupt automatically on board sound is in use.

 

Due to the fact I can't disable the on board sound, I think I can not use any PCI sound card at all.

 

 

 

I also tried a cheap no name USB Audio stick which will be shown in system preferences and works fine, but this is stereo only.

 

Does anyone knows a USB sound card with AC3 SPIDIF out? Koaxial or optical.

 

Thanks