The Medway Handyman wrote:

SWMBO has some wireless headphone which plug into the 'phones' socket on the
hi-fi (Sony).

So, question is; Can I just use a speaker extension lead of say 10 metres
which will plug into the 'phones' socket and connect the other end to some
outdoor speakers? Like these?
http://www.maplin.co.uk/Module.aspx?ModuleNo=221776 I could build a box for
them out of deck boards

You can only really use the phones socket to drive small loads like a
set of phones, or another amplifier which could in turn drive the
speakers. A feed from the main speaker terminals would be best (better
still of the amp directly supports two outputs - some do.

The speakers you link to claim to be "twin cone" - which suggests a
construction not unlike some car speakers with a tweeter mounted in the
throat of the woofer - so a simple box is all they need really - they
probably don't need a separate tweeter and crossover.

You would need to make a proper enclosure for them. Since this is for
use outside an fully enclosed "infinite baffle" box would be best (i.e.
no reflex ports etc). Perhaps a WBP ply box that you could clad with
deck boards to make it blend in better. Seal all the joins with
silicone, and stuff it with some wadding.

Would I lose anything over the cable length, what ohms do I need & how would
I connect the cable to the speakers - bearing in mind I am to electronics
what Colonel Custer is to Indian fighting.

I would use some flat T&E so you can dress it neatly where you want it.
1.5mm^2 ought to be adequate.

--
Cheers,

John.

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