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View Full Version : Digital audio, S/PDIF - I'm a bit confuzzled.



wratterus
14-04-2009, 03:36 PM
Recently picked up an Onkyo Home Theatre receiver for cheap, it's got three S/PDIF inputs. 2 digital optical, and one digital coaxial.

I've got the Xbox 360 running through one of the optical jacks, and the Freeview receiver through the other. Works like magic.

I'd like to use digital optical for the PC too, with the cables being a lot cheaper and easier to source, however the only digital jack left on the receiver is the digital coaxial input.

I'm now on the hunt for a cable, 3m or 5m, and there is a massive difference in cost between some seemingly identical cables.

Theres a few cables I've found on trademe, but I'm not too sure if all the cables are the same, or if some are going to transmit a lower quality sound, are there 'digital coaxial' cables and then others, that type of thing. Done some googling but can't really seem to find a solid answer.

Got my eye on one of these cables, is there a difference between them?

http://www.trademe.co.nz/Browse/Listing.aspx?id=212256802

http://www.trademe.co.nz/Browse/Listing.aspx?id=212824897

Thanks guys. :)

wratterus
14-04-2009, 04:00 PM
BTW - a 4 - 5m Belkin cable from ascent is looking to be around $100. :eek:

Erayd
14-04-2009, 04:05 PM
Total ripoff. Just grab any old RCA-terminated cable from the $2 shop and you'll be sweet. As the signal is digital, it doesn't matter how crappy your cable is as long as the signal reaches the other end - it'll still sound perfect.

CYaBro
14-04-2009, 04:06 PM
Just use a normal RCA cable, works fine and you won't notice any difference as it is a digital signal.
It follows the same theory as the HDMI cables, the cheap ones work just as well as the $300 ones.

SNAP!

Blam
14-04-2009, 04:10 PM
In am home threatre advanced cables don't really make a difference over a short distance, so I wouldn't fret too much about finding the right cable

Look for the 75-ohm impedance when buying the cables, its the mininum for a good coxial cable.

the second cable you listed seems dodgy...no mention of impedance over distances.

Blam

Blam
14-04-2009, 04:13 PM
Just use a normal RCA cable, works fine and you won't notice any difference as it is a digital signal.
It follows the same theory as the HDMI cables, the cheap ones work just as well as the $300 ones.

SNAP!

But a simple analog RCa cable is unshielded...over 3/5m wouldn't there be a large amount of signal loss, and there could be interference from other electrical devices easily..

wratterus
14-04-2009, 04:16 PM
Heh, awesome. Thanks guys!

I do have an ungodly amount of stuff running in that corner of the room, so if theres anything thats going to interfere with the signal, it'll be gaurnteed to do so. :p

Just had a look on Ingram Micro on the offchance they had something and a 3.6m 75ohm belkin cable is way cheaper than on trademe, so that's cool aswell.

I'll try a RCA cable tonight, see how that goes.

Erayd
14-04-2009, 04:21 PM
But a simple analog RCa cable is unshielded...over 3/5m wouldn't there be a large amount of signal loss, and there could be interference from other electrical devices easily..

Still doesn't matter, it's a digital signal - more than enough will get through to be decoded, and you won't lose any quality. And being digital it won't be affected by interference either. As I said earlier, as long as it gets to the other end, everything will work perfectly with no quality loss.

SolMiester
14-04-2009, 04:44 PM
try cablesdirect.co.nz....i got a 5m rca cable for $4.72 the other day, cost $4 freight for next day delivered...

wratterus
14-04-2009, 04:52 PM
try cablesdirect.co.nz....i got a 5m rca cable for $4.72 the other day, cost $4 freight for next day delivered...

Cheers.

sroby
15-04-2009, 09:57 AM
Look for the 75-ohm impedance when buying the cables, its the mininum for a good coxial cable.


MOST RCA 75ohm cables arnt 75ohm, true 75ohm RCA plugs are pretty rare...
no big deal in this case anyhow :banana:banana

Some of the $30-$50 audio cables Ive seen are just made to look more expensive, the actual cable quality under that thick outer sheaf was pretty poor.

Blam
15-04-2009, 02:12 PM
MOST RCA 75ohm cables arnt 75ohm, true 75ohm RCA plugs are pretty rare...
no big deal in this case anyhow :banana:banana
Whats the deal with saying 75ohms on the description page then??

So they're lying? You do realise I'm talking about digital coxial right?

Speedy Gonzales
15-04-2009, 02:18 PM
An Xbox 360 has optical outputs?

Must have a different model then. Or do you mean HDMI?

wratterus
15-04-2009, 02:26 PM
Yar, optical audio. It's just on the back of the Xbox end of the AV plug.

http://www.vavolo.com/C/CAB-XBOX360-2_3.JPG

The little jack on the lower left. Halo in 5.1 is much more fun. :D


http://www.amazon.com/Xbox-360-Component-HD-AV-Cable/dp/B000B6MLPU

Thats the exact cable we're using here. Component video out and optical for the audio. Quality is A+.


http://img229.imageshack.us/img229/4594/optical2zw.jpg

http://askville.amazon.com/Xbox-360-Arcade-optical-audio-output/AnswerViewer.do?requestId=5542450


If you don't have the component/optical outputs you could probably pick one up off trademe for not much.

Speedy Gonzales
15-04-2009, 02:40 PM
Hmm ok then. I've got that cable, it came as part of the Xbox when I won it :p Not that I use it tho, since its hooked up to the monitor.

I should replace this TV (29') with this monitor lol.

Since we dont watch TV anyway. The only thing, I would need is some way of connecting the stereo's DVD signal to this monitor (since the stereo doesnt have HDMI). And get some kind of HD tuner. Then I'll chuck this case and this monitor in the cabinet. If the Xbox could play all zones, it would be OK (but it doesnt)

wratterus
15-04-2009, 02:43 PM
Yeah, there is some seriously annoying things with the Xbox. It's almost there as a home entertainment unit-ie thing but not quite. :p

nitram9857
15-04-2009, 02:48 PM
What, You have an optical out put with the S/PDIF That needs a fibre optic cable, as per this . http://www.trademe.co.nz/Electronics-photography/Home-audio/Cables/auction-213038486.htm the out put is from a laser diode and is sent down the glass core in digital.:punk

Speedy Gonzales
15-04-2009, 03:04 PM
Yup its not that digital / optical connection tho.. Its a normal RCA plug (for the Xbox, that is)

I've got a souncard with optical / coax connections on it, and one fibre optic cable, like the one you posted. But nothing to connect it to :lol: