Stereo / speaker socket, what is this cable?

[sophiekhan]

Moved into a new flat where there are two expensive ceiling speakers fitted. Exciting! However, plugged my amp into the speaker socket and couldn’t get any output.

Having opened the socket, there is a cable in there not connected to anything. Nothing is connected to the face plate. It doesn’t look like speaker cable to me… is it coax?

There is no obvious other cabling point in the house. I am fearing the speakers either cabled in, or have been plastered over. Any ideas how I can track them?

 

[jado84]

I've never cut open a coax cable so don't know what they look like inside, but the single conductor makes me the suspicious it might be. Is there any writing on the sleeving of it? Is it just the single middle conductor, and no conductors in the five triangles surrounding it?

Based on where the box is, could this have been an aerial feed that someone has repurposed for speaker terminals, and just snipped off the existing coax?

May be worth taking the speakers down and seeing if there is speaker wire attached to the terminals and (if they are present) the rough direction they head to. Might be someone has installed the speakers but never got round to running the speaker wire. If there are speaker wires you could look with a cable tracer.

If no slack has been left, the speaker wire might have just slipped up out of the box if someone took speakers down to put different ones in (e.g. swapping their own speakers when moving out).

 

[JohnD]

I think it is air spaced co-ax. There is a copper conductor in the centre, then the plastic fins to keep it centred, then there should be a copper braid of hair-thin wires round the outside, (then sometimes a metal foil wrapping) and then the outer plastic sheath. If looks to me like it has been chopped off. If there had previously been a connector, there would be indentation marks round the outer sheath.

The five triangles are intentionally full of air, not wires. They are just spacers.

 

[JohnD]

If you can lay your hands on a multimeter, you could probe the wires and see if anything is connected to them. Co-ax is most often used for TV aerials, also for VHF radio sometimes, and for satellite or cable TV. I suppose if you had a lot spare you could use it for speakers but AFAIK it is not usual.

 

[Roy Bloom]

Your post doesn't add up.
You say there are expensive ceiling speakers fitted, but when you look for them, you can't find them?
If you have no idea where they are, they could be anywhere, in the shed, in the loo, on the patio, next door.

If you can't find them, how can you estimate the value of them? It's the speakers that provide the value, not the wiring.
You might have the wiring installed, and it wouldn't take much to reconnect the face plate socket in the wall. But not knowing where the other ends of the wires are, what's the point.

You need two double wires going from your amp to the speaker sockets, and there will be two double wires going from that socket to where the speakers were. Coax would provide that, but it's not the best. Then they'll probably exit the wall, plaster, floor, or anywhere, and connect straight to where the speakers were.
Coax could work as speaker wire, but it's not the best, and suggests the installation was not expensive.
You might also need a change-over switch for your amp, assuming you want to switch the sound from your normal room speakers to the remote speakers, asuming the other speakers were remote. Some amps have this function available. Otherwise a separate switch is required. You might need to verify your amp can cope with two sets of speakers simultaneously. If your amp has a 1, 2, or 1 & 2 speaker switch, it's probably safe to assume it can.

If there is only one wire in the socket, it suggests that the speakers were not wired for stereo, only mono. There mght only be the end of one double wire sticking out of somewhere.

Then again the socket could have been used for something entirely different, like connecting a remote satelitte tuner to a TV, where coax might be the norm, prior to Cat 5 for internet connected TV.

 

[RandomGrinch]

Moved into a new flat where there are two expensive ceiling speakers fitted. Exciting!

Have you checked for Bluetooth?

 

[Lucid]

Apologies in advance to any electricians here present, but this looks like an electrician's bodge in a new build. Rather than admit they haven't a clue when it comes to AV and TV aerial cabling, they just blunder through trying to wing it with what they know from mains wiring without realising (or caring) that things work differently in other industries.

As long as it looks okay to the QS then that'll do, even if it doesn't work.

The wire behind the speaker socket is indeed aerial coax. We haven't used airspace coax in decades. Foam filled stuff is the order of the day now. I know that some no-brand Chinese factories have started knocking it out a fraction cheaper than the cheap crap 'RG6' normally sold by electrical trade wholesalers. Some sparks will stoop to any level to make an extra penny on the job.

The way it's looped through is common to how sparks run mains twin & earth for wall sockets. I see this a lot behind aerial faceplates in new builds. They just loop a single cable daisychain fashion from TV socket to TV socket.

You might be lucky though. This could be the end of the double cable run to those speakers you think might be somewhere. It's not the right cable type, especially for expensive in-ceiling speakers, but maybe its at least a connection, so you can do a bit of searching.

Regarding speakers, there are brands such as Amina which are designed specifically to be plastered over. They use a tactile transducer rather than a conventional speaker cone set. It vibrates the wall and turns it into a speaker. Similar tech has been used behind the wall panels on commercial passenger jets, and Sony uses this on their top-of-the-range TVs to turn the TV screen into a speaker.

Cut the cable, join on some speaker wire, then retest.

 

[RandomGrinch]

Cut the cable, join on some speaker wire, then retest.

I would like a peep at the rear of the euro modules first - if there were remains of cable on some solder tags, or if there was no evidence of any connections at all; these could simply be put in place to cover a conspicuous gap!

 

[oldbutnotdead]

A pic of the 'expensive' speakers would be useful, as would an investigate of any visible wiring at the speakers. As others, that is very cheap coax, not suitable for low impedance speakers.

 

[opps]

Am I missing something? How could coax be used to power stereo speakers?

And to the OP, how do you know that the speakers exist? Can you not ask the previous owner how to interface with them?

 

[flameport]

Can you not ask the previous owner how to interface with them?

They won't know, because they won't ever have been used even if they exist.

Have seen similar in many properties, typically those built around 20-25 years ago.

Supposedly high end audio system installed at new build. Looks impressive from a casual viewing, but in reality it's just random junk, none of it was connected properly or at all. Today it's all unusable and obsolete.

 

[Roy Bloom]

Am I missing something? How could coax be used to power stereo speakers?

It'll work in a fashion. You only need two wires for mono, (four for stereo, thus two coax wires). A coax has a central wire, and is surrounded by a metallic threaded sheath, which could act as a second poor quality wire. You just need to take care when connecting the metallic sheath.

 

[Roy Bloom]

Today it's all unusable and obsolete.

Bluetooth?

 

[flameport]

Bluetooth?

20+ years ago Bluetooth barely existed, and certainly wasn't used for home entertainment equipment.

 

[Roy Bloom]

20+ years ago Bluetooth barely existed, and certainly wasn't used for home entertainment equipment.

Yes I'm aware of that. You said today the wiring is obsolete. I asked if that was because Bluetooth had replaced it?