[mythtv-users] optical vs coax (was My Ultimate Mythtv?)

Jarod C. Wilson jcw at wilsonet.com
Wed Sep 17 19:03:45 EDT 2003


On Wednesday, Sep 17, 2003, at 03:42 US/Pacific, Per Åge Sørvik wrote:

>> I can definitely see the argument that a signal having to be 
>> translated from one medium to another and back is bound to have a wee 
>> bit more loss of signal than one that never needs translation during 
>> transport.
>
> This kind of conversion doesn't really have a loss in the form of 
> "loss of data" at all, as in different sound quality. 1 is 1, and 0 is 
> 0. Som audophiles will probably start talking about jitter or 
> something though.

It isn't always 1 is 1, 0 is 0. Sometimes it is 0.9 is 1, 0.2 is 0, and 
0.6 may have been intended to be 0, but comes out 1. Highly unlikely, 
unless something is very wrong, but bit-flipping is still possible on a 
digital signal.

>>> On the other hand, optical cables are immune to electrical noise.
>>
>> Good point. The superiority of coax over optical argument does assume 
>> you have high-quality coax cables that are well-shielded. Optical 
>> might be better if you have an issue with lots of electrical 
>> interference. Optical also has the advantage of being able to span 
>> much greater distances, so if you want to put your stereo 500" away, 
>> you can... :)
>>
> That depends on the quality of the optical cable (attenuation)

But of course.

> and the fact that toslink probably is multimode fiber, not singlemode.

Not sure.

> I really don't think the normal optical consumer cables can cover very 
> large distances (more tha a few meters). Haven't teset it though. I 
> have testet some 20m shielded coax, that worked just fine.

Hm. I was extrapolating from 100BaseTX versus 100BaseFX, but then I'm 
not seeing many very long optical toslink cables on the site of the 
dealer I use for cabling... Perhaps you are correct.

> People should use whatever is appropriate in their situation, without 
> worrying about sound quality.

Yes, like I said before, either optical or digital is going to be 
pretty damned good, and kick the pants off analog.

> Personally, I like optical cables because of their usually smaller 
> dimensions & plugs.

But they're also more fragile (I'm playing devil's advocate). I use 
both myself, and really have no beef with either one.

> All IMHO of course.

Likewise. :)

--Jarod




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