Speaker wire in-wall

[Blaggins]

Hi guys, hoping someone can help.
I'm hiding some speaker wire behind my skirting boards for my surround sound, and want to conceal the run up to my speakers (roughly 1m from floor to speaker).
House is dry-lined, so figure so figured I'd make a hole at speaker height, and another at skirting height and pull the cable through.

However, I wanted to check if there was anything I needed to be careful/aware of? And specifically, if it was safe to run speaker wire behind plasterboard like this? I've seen talk of fire-rated "in-wall" cable, but this seems to be on American sites, and I can't find any mention of fire rating or in-wall use on any of the speaker cable I've looked at.

Thanks!

 

[Sam Gangee]

There's a link to a fire safety document on this page:
http://www.satcure.co.uk/tech/tvmounting.htm

There are two considerations:

1. Smoke and fumes caused by burning insulation.

2. Passage of fire to an adjacent room or dwelling.

1. Requires the use of Low Smoke & Fume cable.

2. Requires holes between rooms or cavities to be sealed or otherwise protected to prevent passage of flames.

I don't know if "loudspeaker cable" is available but bear in mind that you can use ANY multistrand cable or even coaxial cable. The audio frequencies are so low that the type of cable really won't make any audible difference. In fact some "audiophiles" insist on using coaxial cable "because it sounds better" (which I personally doubt).
See http://www.satcure.co.uk/accs/WF100_cable.htm#audio

Frankly, unless you plan to use masses of cable, I wouldn't worry about smoke and fumes. Cable behind plasterboard should be OK for several minutes in a fire.

 

[Blaggins]

Good info, thanks Sam!

So, there's only going to be about a metre of cable behind the plasterboard (x2), and the holes won't go through to the next room or outside, only into the cavity and then back out again. So is it fine to use normal speaker cable in this case?

I have labgear/philex 42 strand twin core figure of 8 cable from screwfix.

 

[feynman]

Just to make an "anorak" point; the best speaker wire (between the amplifier and speaker) is as thick as possible with as many strands as possible.

Any wire will produce a sound, but thin wire will restrict the bass frequencies and the so-called damping, which affects the attack of percussive sounds. The more strands the wire has, the less the high frequencies will be restricted.

Twin core is fine, Coax is only required for low level audio frequencies, such as from a microphone or turntable, and any inputs to an amplifier.

So don't use bell wire, but get as thick and as multi stranded twin core as you can. What you're using looks about right.

 

[Blaggins]

Just to make an "anorak" point; the best speaker wire (between the amplifier and speaker) is as thick as possible with as many strands as possible.

Any wire will produce a sound, but thin wire will restrict the bass frequencies and the so-called damping, which affects the attack of percussive sounds. The more strands the wire has, the less the high frequencies will be restricted.

Twin core is fine, Coax is only required for low level audio frequencies, such as from a microphone or turntable, and any inputs to an amplifier.

So don't use bell wire, but get as thick and as multi stranded twin core as you can.

Thanks Feynman. So do you think the 42 strand wire i've got is good enough for a 4-ish metre run? It's certainly thicker than the stuff that came with the amp system that i had been using!
I've also got a 10m reel of Shark 12AWG speaker wire that's REALLY thick (no idea how many strands), but it's so thick i'm not convinced it would fit in the terminals on the back of my amp!

I've already run the 42strand stuff behind skirting boards to my rears. so hopefully it's ok!

 

[freddiemercurystwin]

Your amp takes banana plugs right?

 

[feynman]

Oops, sorry, we crossed - I just edited my previous post.

Yes, don't lose any sleep, but the fatter and more strands the better. What you're doing looks about right.

 

[Blaggins]

Your amp takes banana plugs right?

no idea!
i'd guess so though.
the outputs for the fronts have screw-down terminals, but possibly take a plug as well (there's a hole in the screw cap, if that makes sense?). The other speakers are all the little spring-loaded ones though. As are the terminals in the backs of the speakers.

I'll have a look tonight.
The amp's an entry-level Onkyo. Came as a set with the speakers.

 

[freddiemercurystwin]

Sounds like it does, any amp that can't even accommodate banana plugs its really not worth worrying about the speaker cable.

 

[feynman]

Not strictly true, although generally, an amp with small spring terminals is unlikely to be more powerful than an amp with big chunky screw terminals, (banana terminals indicating something between these two).

It is the total resistance and construction of the cable between the amp and the speaker that is important. So even if you can't get all the wire in the terminals, there will still be a benefit to using thick mutli stranded wire, especially over a long cable run.

Having said that, hearing the difference will depend whether you are a critical hi-fi listener, or if you just want to hear background music or the telly and are not bothered about the absolute quality.