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Discussion Starter · #1 ·
Sorry to start a new thread, but im not finding what i want to know. This forum is very confusing!


I want htpc to send audio to external a/v receiver. Questions:


1. I gather this is done via sp/dif? Is the sp/dif the same as the coaxial digital input on a/v receiver, or does it need conversion? If so, what u use to convert it? Where you get cable? Or is it sent through the optical digital connection to the receiver, and if so, what does that conversion?


2. The dvd drive itself has a sp/dif connector on it, can you use it directly? Or is it for cd and not dvd?


3. When playing dvd from hard disk, i presume you must use sp/dif on sound card, but is (2) ok if your playing from dvd?


Price on pc is skyrocketing, please dont say i need $200+ M-audio card too...


All for now, thanks much!
 

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newtbert,

1. you need a mono miniplug to rca cable to attach from digital out of sound card (at least most of them) to the coax input of the receiver.

2.You can use it, but it is not necessary at all.

3.No, it needs to go through the the IDE cable
 

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Paul already answered the questions, but here's the long version if interested ...


1. Audio can be sent to your receiver either in analog or digital form. If digital, this is almost always s/pdif, which has 2 different means of transmission; 1. 'coax' or 2. optical (toslink). If using coax digital, the cable is available at any A/V oriented store or even radio shack. The S/PDIF from a soundcard or onboard (motherboard) chipset is the same as the s/pdif on your receiver.


2.1 "Note on HDR-2 (2 pin header) interface used in some PC products:

Many modern PC CD-ROM drives and some soundcards (SB32, AWE32, etc.) have a two pin digital output connector in the back of the drive and they sometimes call that interface S/PDIF. Unfortunately the electrical signal which comes from it is not exactly what is described in S/PDIF specifications. The data format is exactly the same, but the signal is TTL level (5Vpp) signal instead of the normal 1Vpp signal. The output level might be selected to make the interfacing to other digital electronics easy when signal is travelling inside the computer (the normal output driver system and input amplifiers can be avoided). The downnside of this is that you need to build some electronics to make the signal from the CD-ROM drive to match what normal S/PDIF equipments expect."


Source: http://www.epanorama.net/documents/audio/spdif.html




The older soundblaster live! (early models only) soundcards had output on the outside that were called s/pdif meant for connecting to receivers but they turned out to have TTL voltages (e.g., 5v) instead of the s/pdif spec'd voltage (e.g., .5v) they should have been at. For most this did not hurt the receiver, but supposedly for some Denon owners it did.



2.2 The 's/pdif' 2 pin output (which is really TTL, see above) that is in the back of many ROM drives is there for CD audio only (and incidentally isn't needed since most OS's and software players can read the audio from a CD as data over the ide connection). The audio that is in a DVD is easier to understand if you think of it as being part of the movie's data, which 'enters' the computer through the ide cable just like any other data.


3. For playing a DVD movie, the audio is part of the datastream being read off of the disc. This means to get audio into your receiver your choice is either a soundcard or a motherboard that has audio chipset built in. Your other choices being analog vs digital, decoding in the computer vs decoding in the receiver, etc...
 

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Discussion Starter · #4 ·
Awesome replies, thank you so much! Seems i wasted allot of time with the "faq"... very good explanations!
 
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