Alarm cable as surround speaker wire?

craigj

Established Member
Hi,

Am about to move to a new house and the carpets are being laid in advance, I need to wire up my surround speakers and wondered about alarm cable? 4 core so could use 2 cores for each surround speaker?
 

dante01

Distinguished Member
Why use cable other than speaker wire? There's no reason to prevent you from using wire not intended for use with speakers, but the conductor may not be as conductive as that associated with most speaker wires and the insulation may also not be as effective as that used with some dedicated wires. Twin and earth works well, but the copper isn't oxygen free so slighly less conductive when compared to similarly gauged dedicated speaker wire. A friend of mine swears by the cables you find on vacummn cleaners, but he also believes Elvis is still alive and well.

What is the alarm cable constructed from, how thick is it and over what distance will it convey the current to your speakers?

The 4 cores within a single run shouldn't ideally be used to carry both speaker's current. It is a bad idea to run cables associated with two separate channels in parallel with one another. You may experience crosstalk between the cables in such a configuration?
 
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Trollslayer

Outstanding Member
Speakers carry quite high currents at low voltages so you could have problems.
you can get speaker wire for bi-amping which would solve the problem.
 

noiseboy72

Distinguished Member
I use alarm cable, as it fits neatly along the skirting board. Admittedly, only for the last 5' or so. Surround sound tends to be much lower in volume and unless you are using full range rears - not small satellites, then you don't need to worry too much about current, as I doubt it will ever get over 20W or so.

You can however, get 4 core mains cable in a neat white flex as well. 4 x 0.75mm is quite small and will run surrounds very happily. I use some 4 x 2.5mm to run my passive sub, which is quite thick, but still domestically acceptable.
 

Trollslayer

Outstanding Member
Part of the problem is that speaker impedance changes significantly with frequency but the cable impedance doesn't so you will be changing the frequency response as well.
 

noiseboy72

Distinguished Member
Hmm, not sure on domestic lengths of cable this would be the case. Stick 30M of cable on, maybe, but 5M, I would doubt it very much. The resistance is only about 0.1 ohms per meter on 7/0.2 cable, so I doubt you could measure or hear any difference.
 

Ghostrider

Established Member
Several years ago I had cabled up the rear surround speakers using some poor quality wire - it worked fine with my (at the time) All-in-1 surround sound package.

When I put in my AVR and turned the olume up a bit the rears would cut out - I can only assume that the cable insulation was breaking down and going short circuit as the AVR protection circuits had obviously cut in.

Re-installing with some better quality but still what many would consider budget - (£2/m or thereabouts) cable solved the issue once and for all.
 

Trollslayer

Outstanding Member
AV receivers can deliver big surges so it's possible.
 

noiseboy72

Distinguished Member
I would suggest you had a cable fault, as alarm cable is rated to 60V AC and has at least 500V insulation.

7/0.2 is not ideal, but quite usable.
 

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