Which audio cable?

alicegoody

Member
2020-01-25 3:51 pm
Hi sorry I'm a complete amateur with these things! I've recently taken over a room which has speakers in the roof. However, I do not currently have any cable to go into a socket in the wall to connect to something like my laptop. I'm assuming that I have to connect a cable into the red and black sockets and that the cable has to have a headphone jack at the other end to connect to my laptop... but I've no idea which cable I need to buy for this?

I'd really appreciate any help with this - thank you so much in advance :)
Ally

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New members are not allowed to post picture I believe, which prohibits bots from putting up ads for enlargers and other trash.
When you can post pictures, you have to push the "go advanced" button below your reply, to link to the image you have loaded on your PC hard drive. Cell phone users you're on your own, my cell phone doesn't upload images.
In general, your laptop will not drive any 8 ohm speaker. There are special 24 ohm speaker sets which will plug in a 3.5 mm stereo earphone jack, which are barely audible in a very quiet room, I have a pair. But in general you will need a power amplifier, of at least 10 watts to be heard over city noise. The cable to go from laptop to amp input is usually a 3.5 mm stereo plug to dual RCA plug adapter cable. Some amps instead come with a 3.5 mm stereo receptacle, or more professionally, dual 1/4" phone jackes. I get my cables from newark.com (farnell USA). Then from the amp speaker terminal to the wall device, depends on the amp output type and the wall fixture type. 1/4 phone jacks are popular, which I do not recommend as if you trip over it it pulls out part way, shorts your amp, and burns it out. Dual banana jacks that are also binder terminals are popular, which can be used with dual banana plugs screwed on to zip cord (dual speaker wire). 16 ga speaker wire is adequate for 10-50 watt speaker signals.
Until you update your profile to show what country or hemisphere you are on, I'm not recommending a source of power amps. In the USA parts-express.com has some cheap ones that mostly work, but don't import any oriental made product from USA to Europe, Africa, S America, Australia etc.
 
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Galu

Member
2018-04-17 6:50 pm
Hi! Someone really should have explained this set up to you when you moved in! :)

Firstly, you wouldn't connect a laptop directly to loudspeakers, you would need some form of amplification of the headphone signal.

Looking at the photo, it may be that amplification is included in the in-wall system and that the two pairs of red and black 4mm sockets to which you refer may actually be outlets for free standing speakers and not inputs to the ceiling mounted speakers.

Without being there, I can't personally say how this system works. However someone with the relevent experience will know.

The 'Parts' subsection is not the best place for this thread so I'll see if I can get it transferred to a more suitable location.
 

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alicegoody

Member
2020-01-25 3:51 pm
Which cable

Thank you so much for your reply! I'm hoping that I've attached the images of what I'm trying to connect to as well.

I think that I have an amp in my garage that could hopefully connect - I'm assuming that whatever fits in those red and black sockets would have bare wires in the end that I can just snap into the amp?

Sorry - It's obvious that I'm in unchartered territory here!

I'm in southwest UK, by the way... I'll try to find a way of updating my profile :)
 

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Galu

Member
2018-04-17 6:50 pm
I'm assuming that whatever fits in those red and black sockets would have bare wires in the end that I can just snap into the amp?
I'd like first to be sure that these are, in fact, inputs to the ceiling speakers.

Those are 4mm sockets and you need two cables fitted with 4mm plugs to plug into them. You'd need to inspect the rear of your amp to see how the cables connect there - sometimes it's bare wire connectors, but more commonly these days it's 4mm sockets.

Two pairs of these would do (different lengths are available), you can always cut the plugs off one end if necessary. MutecPower ULTRA Series Speaker Cable 14 Gauge with Dual Color Pro Series Banana Plugs 3m High Strand Count Copper (OFC) Construction -3 meter: Amazon.co.uk: Computers & Accessories

To connect laptop headphone socket to amp you would need a 3.5mm jack to 2-male RCA plug cable. AmazonBasics 3.5mm to 2-Male RCA Adapter Cable - 1.2m / 4 Feet: Amazon.co.uk: Hi-Fi & Speakers

However, I wouldn't go ordering anything until we are certain of the exact layout of your system!
 
Those red and black on the right do appear to be dual banana jacks which are commonly associated with speakers.
A dual banana plug from farnell or RS (uk distributors) could connect an amp with those outputs to those inputs. https://www.newark.com/mcm/24-2600/connector-type-a-banana-plugs/dp/26C9853
The link is the US warehouse, they may have something else in stock in the UK. I searched "dual banana plug cable". 6' is rather short, they probably have 12' and 20' ones.
To seriously determine if those are speaker connections on the wall, measure from red to black with the ohmmeter scale 200 or x1 of a DVM. https://www.newark.com/tenma/72-13435/dmm-handheld-manual-2000-count/dp/52AC3272
If the resistance if from 6 to 8 it is an 8 ohm speaker. If the resistance is 3 to 4 it is a 4 ohm speaker. If the resistance is 199.9 on 200 scale, then that is the input to an amplifier, or the wires are broken.
If you want to buy that meter in UK you'd search farnell UK site for 52AC3272. Or look for a DVM with an ohms 200 scale or an ohm x1 scale. they had cheaper ones that won't be very accurate at 6 ohms. You'll need a battery for that too, look to see what one it takes & order in same box. Farnell & RS charge freight, the secret to using them is put everything in the same box. Freight is all the same price up to about 2 pounds. Royal Mail may be cheaper than UPS, check that option at checkout to see.
You can buy cheaper stuff at ebay; I find I get no trash from farnell. Meters you'd like to know that the numbers are sort of real. Tore open an entire organ tremelo unit last year looking for a bad solenoid only to find that my co-worker's cheapo meter was lying to us.
 
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Galu

Member
2018-04-17 6:50 pm
To seriously determine if those are speaker connections on the wall, measure from red to black with the ohmmeter scale 200 or x1 of a DVM. https://www.newark.com/tenma/72-13435/dmm-handheld-manual-2000-count/dp/52AC3272
If the resistance if from 6 to 8 it is an 8 ohm speaker. If the resistance is 3 to 4 it is a 4 ohm speaker. If the resistance is 199.9 on 200 scale, then that is the input to an amplifier, or the wires are broken.
Yes, that's exactly the kind of investigation that must take place before committing to further action.

If you can't follow these instructions yourself, then I'd look for the assistance of a technically knowledgeable friend or a professional installer.