JodyP

Cat 5 for speaker wire?

I noticed that the installers that did my pre wiring used a single run of Cat 5 for my center channel speaker which will connect to a wall plate. Is this typical and sufficient?

Also, The coax cable they ran is not marked in any way. How can I tell if It's 75 ohm?

chris_everett

2nd question first: What's the coax for?

1st question. CAT-5 for a speaker line is _not_ typical, and I would say not sufficient either. CAT-5 uses (IIRC) 24awg wire, which is _way_ less than optimal for speaker wire. Even most cheap HTiB's come with 18awg, and I recommend 12. I would have them replace the center channel wiring, and they should be able to tell you what they ran for the coax too.

If you had to, you could combine 4 of the conductors for each conductor on the speaker line, and you might be Okay, but I would want the installers to do the job right.

--Chris Everett

JodyP

Chris,

The coax runs from where my tv will be mounted to where my components are. Receiver,DVD, cable etc...

After posting the original, I did find where CAT-5 is recomended and used by some in the DIY arena.

Bob McElfresh

Hi Jody.

You have to read the fine-print. The people that use Cat5 use 8-12 runs and slit the outer sheath then braid the tiny wires together to create something close to a 12 ga speaker wire. They repeat this once for the "+" side and once for the "-" side to each speaker.

A single run of Cat5 is not good speaker wire. In fact - since you are pushing WATTS of power to your speakers - cat 5 wire is a fire-hazard. It was never designed to carry more than micro-watts of current. (You are sending .. 5 - 80 watts to each speaker?)

Coax - almost all coax is 75 ohm - good for Video, audio and coaxial-digital.

But .. you typically have 3 different kinds of video signal in a home system:

- Composite - single RCA cable
- SVideo - 2 wires with a funny 'keyboard' connector on the ends
- Component - 3 matched RCA cables

If they only ran 1 coax cable to where your TV is - they did a crappy job. You can only run Composite video and this is the poorest type of connection. No way can it handle HD video.

The only way the wires you described would be useful would be if they are left as a "fish roap" to pull the better cables through the walls.

Are the installers finished? You didnt pay money for this did you?

JodyP

Bob,

Thanks for the reply.

Actually there are 5 coax cables and one Cat5 wire. I'm assuming that three of the five coax are for Component Video run for DVD, one for Composite and one for Digital Audio. I'm not sure what the Cat5 wire is for but there are no speaker wires run for the center channel.

Maybe the wiring for the center channel just didn't get done but what could the Cat5 be used for?

TIA

chris_everett

5 coax to the TV is probably fine, reagardless of impedance, and like Bob said, it's probably 75 ohm anyway.

Cat5 is mostly used for computer network wiring, although it can be used for other things too. But regardless, it's not speaker wire, and I don't know what, if anything, it would be intended for, at least on it's own.

--Chris Everett

Dick Knisely

If it were me, then now that it's there I'd have them leave the Cat 5 run in place and tell them to do the speaker connection correctly. Depending on where the other end of the Cat 5 run is you might well want it so you can connect the system to a home network. Even if you don't immediately plan to do so, having it there could be a good thing.

I'd also have a phone connection put back there near the system as well for possible use later. Phones normally run on Cat 3 wire but will run over Cat 5 just as well.

I am not young enough to know everything. -Oscar Wilde-