Speaker Wire --> 1/4" Jack Soldering...

WetDaddy

Hey everyone.

I found an old set of speakers from a Philips Hi-Fi that was lying around my house. They're equipped with just basic speaker wire, but I'd like to use these with a Behringer mixer for a basic PA.

The main outs on the mixer are 1/4" (or 6.35mm? Guitar cable size, anyway). Is it possible to simply solder on jacks to the speaker wire?

The speaker wire comprises two wires, which I presume are "ground" and "live". One of them has a white strip on the sheath (y'know, to tell them apart), but I don't know which one this is! I presume it's "live", or is there some kind of standard?

Oh, and while I'm at it, what's a balanced cable? Is it something to do with reducing static? And can any cable be balanced, or does it need 3 pins (a la XLR or a stereo jack) or something?

Man, you guys really should be charging me for this...

Doctor J

Those speakers would be cack for anything serious though. Is there a frequency response spec on the back, or wattage or ohmage? You could solder the wires onto a 1/4" jack easily enough but I'd say you'll blow the bejesus out of them in double quick time.

WetDaddy

Cheers Dr. J.

Just found a tiny sticker on the bottom which says they're 8ohm. There's nothing about a frequency response (except for "Tuned Bass Port" emblazened on the front )

The model is Philips LSB400 or LSB400/10, but I can't find out anything about them on the web. To be honest, all I want to do is put vocals through them for mini-rehearsals at my house. We've a drumkit and a sax, but they ain't too loud. They'd be just be so that myself and the bassist can hear if the harmonies are working, etc.

Doctor J

It might work, but you'd need to be very careful how hard you push them. Regular hi-fi speakers just aren't designed for this kind of thing.

Maybe have a look at some cheap and cheerful monitors from the likes of JBL if they pop sooner than you'd like.

daram

One problem you may have is that they wont be amplified. Unless your desk is powered. In which case you'll the old philips hifi too. And somehow wire your desk into it.

I have a similar setup where we practice. We got a set of small surround speakers and a subwoofer from compustore for about 50euro and made some cables to attach it to our desk. end result being we have one speaker for each of the band. Like mini-monitors. They dont sound great but they're louder than the drum kit so they're grand for practicing.

Eoin Madsen

If you can open the speaker up, it should be pretty easy to determine which is signal and which is earth, but failing that, it doesn't really matter. If you switch signal and earth in a loudspeaker all you do is reverse the polarity/phase. Make sure both speakers are wired the same way and you'll have no problems.

Realistically you'll need an amp to drive them or the level is going to be very low, noisy, and probably quite distorted. If they're hi-fi speakers I'd imagine they must be in the 10-20 watts range, so you could probably buy a cheap hi-fi amp in Maplin (assuming you can't make the actual hi-fi amp usable). If you stay in that wattage range I wouldn't worry too much about over- or under-driving them, just don't turn it up any more if you hear it distort. Get a 4 ohm amp (4 ohms into 20 watts for example), and you shouldn't have to worry about impedence matching. Tbh, I can't imagine it'll really be particularly useful for practicing at that level anyway. Bear in mind that hi-fi speakers are designed for mastered signals with little or no transients. They won't handle a live signal very well. If you can't afford to fork out on something with some decent wattage, I'd recommend you use headphones. You can buy a headphone splitter for about 2 quid, try Maplin.

If you need a speaker, I recommend this: http://www.netzmarkt.de/thomann/thoiw6_the_box_pa108a_aktive_fullrangebox_prodinfo.html It's active, so you can plug it straight into your mixer via an xlr or 1/4" jack.

Balancing is only for line-level signals, not loudspeaker signal, so I wouldn't worry about that. It requires three wires in a proper cable: signal hot +, signal cold -, and earth; and both ends in the signal path have to be balanced for it to work.

eoin5

most hifis will have an aux input of some sort, usually 2 phono sockets on the back. So if thats the case youll need 2 1/4" jack male to Phono male leads (sometimes they come joined together for stereo usage), maplin should have these and you wouldnt have to do any soldering. My first PA had a samsung 400watt rms hifi driving a pair of 400watt (each) bassbins, ahhh them were the days!

Doctor J

Many PA mixers have a built in amp...

Eoin Madsen

This is true. If you plug the powered output of an active mixer into an amp or powered speaker, you'd want to have a fire extinguisher ready.

A 250 watt powered mixer into a couple of 15 watt hi-fi speakers isn't going to be a pretty sight either.

daram

You'd be peeling the speaker cones of the wall on the other side of the room

WetDaddy

Thanks for all the suggestions fellas...

Hmmm, sounds like my plan may not be the best. Perhaps saving up for a pair of speakers mightn't be such a bad idea after all.

If I do go ahead with the wiring and I'm still alive afterwards, I'll let you know how I got on!