Quick optical question

Cairnsey

Cairnsey

Cairnsey

Associate
Joined
2 Jan 2007
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2,305
Location
England
Hi,

I have an audigy1 PCI card with a digital socket. I've connected a '3.5mm to optical' cable and set windows to only output digitally. I may be wrong but, I was sure I should see a red light from the end of the optical connector? I would test it with my AV amp but it's too far away and my cable is small so I can't connect it. I want to know if this will work so I can buy a longer cable+adaptor so I can watch downloads in 5.1. Cheers
 
because my 5.1 home cinema speakers are connected to it and it would be a major hassle unplugging everything else. Am I barking up the wrong tree here?
 
The manual states that I need a 3.5mm mono jack to RCA cable. Thought the only cable which could be used for digital signals were optical and co-ax? Also it says to connect it to my SPDIF input on my amp, which I don't seem to have, only co-ax and optical for digital and RCA/S-video/component etc for analogue. Is it called somthing else?
 
Cairnsey said:
because my 5.1 home cinema speakers are connected to it and it would be a major hassle unplugging everything else. Am I barking up the wrong tree here?
Click to expand...

Yeah, move your PC instead! :)

I don't think it is going to do what you want it to. Creative's optical output will only pass through a 5.1 signal. The sound card won't create that signal. If you are watching a file with AC3 or DTS soundtrack, it will pass that through to your amp. Other than that you'll get stereo. Your amp can probably upmix that if it supports prologic, but that's not 5.1.

If you are feeling flush... http://forums.overclockers.co.uk/showthread.php?t=17843525
 
So effectively my PC's sound card is decoding the signal and my receiver is just used as an amp?

Also, I don't think it's an optical cable I need as mentioned above. So, how can my amp seperate and amplify 6 channels through one analogue cable? It confuses me.
 
Firstly, cables and connectors:

No, you won't see a red light, as that's for optical digital signals only. Optical digital signal cables are terminated with TOSLINK connectors [sometimes mistakenly called S/PDIF connectors]. They're the square-ended connectors.

The other way of carrying digital signals is via electrical digital - this is the one your Audigy uses. Coax/RCA phono connectors are the most common end bits, but technically any type of electrical connector could be used. Creative just used a 3.5mm socket because it could do double duty as an extra analogue out if required.

S/PDIF, by the way, is just the catch-all name for this particular method of digital signal transmission - it's got nothing to do with whether it's optical or electrical, and it's not a specific type of connector. So both optical [TOSLINK] and electrical [coax] connectors are just different types of S/PDIF connectors, and they both carry identical information.

monkeyspank's right about the 5.1 capabilities of the Audigy, too.

And to answer your final question, the cable may be analogue [or more correctly, electrical], but the signal is digital.

All six channels of audio are encoded into one combined digital signal - some soundcards can do this, but as monkeyspank said, Creative's cards can't. They have to rely on being fed an already-combined digital signal. This digital signal is then passed through to your AV receiver, which decodes it back to its six separate parts. So no, it's not just an amp, it's a decoder too.

Hope that helps :)
 
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OK, I got my adaptor (3.5MM mono jack to RCA socket) and a long phono cable. My amp tells me its receiving PCM but when I try a AC3 audio file all I hear is noise and no DD light on my amp. Is this a software problem?
 
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