SPDIF and sound card question

GestaltH

Member
2008-01-21 6:44 pm
Hi,

I am new to the whole DIY audio thing and have a few questions. I have a creative x-fi sound card with an SPDIF output. One question that I have is, does that output contain the signal for all 7.1 channels? Also, can it be made to work at 24 bit and 96khz with all channels? Does this output contain all of the processing that that the analog outputs would normally have (such as 24 bit crystallizer and such), or is it output before that point?

Thanks for any info.
 

GestaltH

Member
2008-01-21 6:44 pm
Thanks for the links. I didn't think to look up AES/EBU for more information.

So, it seems like it is limited to 2 channels and is either 20 or 24 bit. Is there a way to get a digital output for all 7.1 channels from a sound card like this? It doesn't have to be SPDIF necessarily.
 

GestaltH

Member
2008-01-21 6:44 pm
I guess what I really meant was that it doesn't carry any more than 2 channels of uncompressed PCM data. It looks like you can get 5.1 (is 7.1 possible?) pass through on a digital connection but that is still encoded as Dolby Digital or DTS if I am understanding what I have read correctly.

What I was looking for a was uncompressed audio. The only interface that I could find that I liked that could do that is MADI (32 channels at 96k). ADAT lightpipe can also carry 8 channels but only at 48k and I was hoping for 96 or 192. In any case, both of those interfaces are found only on high end equipment (that I have seen anyways) and I don't know how I would go about actually retrieving the individual channel data from the stream anyways.

I still haven't really found a solution to what I'm trying to do. I'll probably make a post later that explains what that is and see if anyone has any ideas about how to implement it. If 8 channels of PCM 96k were available directly from the sound card, it would make what I was trying to do a lot easier.

In the mean time, if anyone has any information on low cost computer cards that support MADI or 7.1 channel PCM over SPDIF or AES, I would appreciate any information. Also, any info on "DIY possible" Dolby Digital or DTS decoding would be nice as well as info on MADI transmit/receive ICs if any exist.