[mythtv-users] New house - any advise?

Steven Adeff adeffs.mythtv at gmail.com
Wed Jan 17 14:58:02 UTC 2007


On 1/17/07, Bill Williamson <bill at bbqninja.com> wrote:
> On 1/17/07, David Brodbeck <gull at gull.us> wrote:
> > Bill Williamson wrote:
> > > However for anything of any power I'd be more worried about heat
> > > effects of resistance (and the ensuing distortion, or even fire
> > > danger) than actual volume degradation.
> >
> > I don't think you'll set anything on fire, unless you're running really
> > high power levels.  CAT5 is made of 24-gauge wire.  I think you'll find
> > a typical home speaker voice coil is wound with wire that's even finer,
> > but it doesn't burst into flame.  If you use too much (say, 100+ feet of
> > a single pair of CAT5) you'll be dissipating as much power in the wire
> > as you are in the speaker -- but the heat produced will be spread out
> > over the entire length of the wire, so no one chunk of it is going to
> > get very hot.
>
>
> I don't really mean that the cable will burst into flame, but if
> you're running music all night fairly loud on 24 gauge wire across
> carpet, it can get uncomfortably hot (from experience).

the reason you run two cat5 cables for pos and two for neg are for
resistance and power handling. If you need more power handling, run
more cable. for small speakers you could run just one for pos and one
for neg and be fine. I've used 18AWG zip chord for small speakers with
no problem, so a single cat5 could in theory be used for both.

Now, the cost difference is not that significant, but for in wall
wiring what makes CAT5 nice is that each strand is individually
insulated. Here's why this makes a difference, CABLE ROT! Insulation
is designed to breath. Not a lot, but enough. In damp areas like under
a house or in walls, etc. this can cause moisture to find its way into
the cable. CAT5's insulation is better than generic speaker wire in
this regard, and due to the individual strands, if one wire gets rot
it won't affect the other strands.

Now here's the kicker, if your running wire for a sub-woofer, like my
dad's dual 15" woofer's, run regular power cable, like the stuff you
use for your outlets! its cheap, thick and perfect for sub-woofer
levels of power at the frequencies that will be going through the
wire! Much cheaper than buying thick gauge speaker wire. Of course, if
you have a self powered sub-woofer then your just running a regular
RCA line to it, so don't do this.

-- 
Steve
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