Axiom Home Page Forums General Discussion Technical Questions Optical Versus Coax...

Is there a difference? Do both support Digital audio? I'm testing out a Onkyo 805 at my house for a couple weeks and it only has 2 Optical connections in the back. So I was thinking of using one of Coax connections.

Josh, optical is a digital connection, while the coax can handle either analog or digital material. There're minor differences, such as the optical connection being inherently immune from outside electrical interference, since it works with light rather than electrical signals, but the typical shielding on coax is good enough interference protection in most home environments. The coax is generally thought to be a little sturdier in its construction. There's of course no difference in the sound quality with either(assuming that any level difference resulting from a difference in the optical or coax output or input sensitivity is adjusted for). Use whatever's convenient.

Cool. That answered my questions. Just wanted to make sure audio wouldn't suffer, :). Thanks.

Its amazing how much a 5ft peice of fiber optic costs!

Not necessarily; for example, MonoPrice has 6' optical cables from about $3-$6.

Both are digital audio, by definition. There's no real difference in terms of sound.

You can use a coat hanger as well, but have to solder ends on first.

Note:

I tried this fourteen times and it never worked.

Damn plastic hangers.

Isn't there a max bit rate capacity difference between the two? I thought Coax had a higher capacity?? I suppose it doesn't matter much anyway, but I am still curious.

You could always rip some Nortel fiber out of the ground. From what i've heard, a good chunck of the material laid across Canada is barely in use yet.
I know some in newer neighborhoods in the US are getting optical fibre right up to the door step and through the house.
We have optical up to the major street intersection near our subdivision but then it is copper the rest of the way in.

I read that devolping countries have such an upper hand when it comes to telecomunacations with wireless and fiberoptic. They never had copperland wires so there's no need to upgrade!

But still those poor bastards have a 10 times better cell phone planes and for only $5 a month! Still dont understand why we get screwed over here. I pay ROGERS $175 a month and my land line BELL is $65 a month! My F-ing cable COGECO is $165 a month.

Yeah Mike, toslink has various bit rate maxes, but they're all more than adequate for the intended use(otherwise they wouldn't work, of course); for example, 15Mb/s is a common one for digital audio use.

Do you know what the max rates of both are John?

I'm not thinking of a time where the max rate could pushed, unless it's a multi channel PCM data stream... possibly.

Okay, now I actually had to go and look up some stuff. For fiber optics, take a look at the Toshiba toslink(Toshiba link)guide which indicates the various data rates(bit rates)that can be handled. For example, at p.15 is a table of their offerings for digital audio, running up to 15Mb/s. They also show other modules which are used when higher data rates(not needed for audio)are involved. So again, an optical connection is available to carry the data load in whatever the particular use is.

For copper coax, there really isn't a similar max that would have any relevance to audio. For example, I quickly found this Belden table which doesn't refer to audio, but lists at p.2 the various video data rates in the hundreds of Mb/s, which of course can all be carried over regular copper coax. So, it's tougher to carry light on the inside of a glass fiber than simply guiding an electromagnetic wave down the outside of coax, but either are available to do the required job.

Thanks John. Sorry to make you study... LOL

How odd. I know that glass fiber works just fine up to 4GB/sec in computer applications. I'm sure it's a different wavelength, and there's multimode vs. single mode, of course, but still...

Ken, those numbers that were linked were just the toslinks that Toshiba makes available; optical connections in general can go much higher when needed, as you mention.

Yup, the technology on each end of the fiber is as important as the actual piece of fiber itself. single mode, multi-mode, single core, multi-core, lasers, LEDs, too short, too long, plastic core, glass, and so on and on.

The good news is that if the Toslink cable has been built to the current toslink standards, it will have all the sufficient bandwidth to cover your multi-channel needs.

The bad news is that if you actually want to send the new High Def sound formats in their pure "uncompressed" form to your receiver, then you are limited to a HDMI cable only. Luckily there are other options depending on your setup.

The really depressing news, if you were not already aware, is that there is not really a LASER in your CD or DVD player shooting the light out into the cable. It's really just a LED light capable of flashing at bionic rates.

Very disappointing, I had taken apart two old cd players and had great plans to mount the lasers on a shark.

"You know, I have one simple request. And that is to have sharks with frickin' laser beams attached to their heads! Now evidently my cycloptic colleague informs me that that cannot be done."

Of course, I didn't even think about the fact they might be using LEDs instead of Laser LEDs.

Of course, the pickups in CD/DVD/whatever players are Laser LEDs, so you should be able to get your shark lasers from that source.