[mythtv-users] New house - any advise?

David Brodbeck gull at gull.us
Wed Jan 17 06:59:38 UTC 2007

Billy Macdonald wrote:
> On 1/16/07, David Brodbeck <gull at gull.us> wrote:
>> Chris Ribe wrote:
>>> Veering off topic here, but this sound like a really questionable
>>> idea.  CAT5 is cheaper than speaker wire because copper is expensive,
>>> and CAT5 doesn't contain much copper.   It just isn't designed for a
>>> high current application like driving speakers.
>> It depends on how long the run is.  CAT5 has a resistance of about 3
>> ohms per 100 feet -- which means 6 ohms for a pair.  If the run is only
>> 50 feet or so, I think it'll work fine.  If it's more than that, the
>> loss of volume may get excessive.
> Remember your physics. Two conductors in parallel will have less
> resistance than the lowest resistance of the pair.  Two 3ohm wires in
> parallel will have a resistance of 1.5ohms.

Right, but what I meant was, when you hook up a speaker you're using a
pair of wires, one positive and one negative.  If the resistance one way
is 3 ohms, the total resistance in the circuit is 6.

You're correct that if you parallel another pair with the first one
you'll halve the resistance.  (And double the capacitance, but CAT5 is
pretty low capacitance anyway.)

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