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PA Speaker connections

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PA Speaker connections

Postby greenstarthree » Thu Apr 12, 2012 1:08 pm

Hi all, just a quick question:

We have a Yamaha MG166CX analogue mixer, which we use into a pair of Wharfedale EVP-X Series Powered Speakers. We’re currently using standard mono-jack cables to do this (instrument cables).


The other day I read a few articles online about the differences between instrument leads and speaker leads, and how using instrument cables for your main PA speakers can cause problems and damage. So I hastily picked up some ‘proper’ speaker cables (with XLR female connectors at the mixer end and Speakon connectors at the speaker end), but haven’t had a chance to try them yet.


I’ve since read a bit more and gotten confused, so just wondered, since we’re using a passive mixer with powered speakers, do the rules about using instrument cable still apply, or is it only for passive speakers from an external amp?


Thanks!
Adam
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Re: PA Speaker connections

Postby Mike Stranks » Thu Apr 12, 2012 1:34 pm

What ho!

For an unpowered mixer connecting to powered speakers then normal 'instrument'/guitar cables are fine. I wouldn't use anything that's two flimsy though as these cables will not necessarily be tucked away and you'll probably have longish cable-runs.

For a powered mixer or separate amplifier connected to unpowered speakers then you would need different cables. Many people use 10-amp 2-core mains cable for connecting amps to unpowered speakers.

The reason is that the output from an unpowered mixer - a 'line-level' output - is at about 1 volt. Speaker cables have to deal with many tens of volts - an amp I've just bought puts out about 40 volts onto the speakers.

That's the simple answer, but I think it's enough to answer your questions.

Cheers! Mike
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Re: PA Speaker connections

Postby greenstarthree » Thu Apr 12, 2012 1:52 pm

Hi Mike,
Thanks for your reply,

Gah! So I don't necessarily need the speaker leads? In fact, from what I’ve read speaker leads are also unshielded, so would they actually be worse due to interference noise?!

This being the case, I assume the switch I need to make (I was getting some buzz/hum with the guitar cables) is to go with a pair of balanced XLR leads? (The Wharfedale speakers have Jack/XLR/Speakon multi inputs).

For example the same cable I’m using to connect my mic’s (SM58) to the mixer, like this one:..?

http://www.studiospares.com/leads-xlr/xlrma-xlrfe-10m-blk/invt/574721/


Sorry for appearing to be a newbie!
Cheers
Adam
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Re: PA Speaker connections

Postby grab » Thu Apr 12, 2012 3:34 pm

Yep, that's the one.
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Re: PA Speaker connections

Postby greenstarthree » Thu Apr 12, 2012 3:42 pm

Crumbs!

Best get on the blower to Studiospares about returning the Speaker leads then!

Thanks for your help guys!
Adam
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Re: PA Speaker connections

Postby Mike Stranks » Thu Apr 12, 2012 3:58 pm

greenstarthree wrote:...Sorry for appearing to be a newbie!...
Absolutely nothing wrong with being a newbie - roll-up and c'mon in is what I say!
... and I'm still a newbie in many aspects - even though I've been involved in sound-stuff for 40 years! There's always something more to learn and that's the great thing about this place - most people are very happy to help if they can.

Much better to ask than guess... some guesses might be very detrimental to your gear - or you!

Mike
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Re: PA Speaker connections

Postby James Perrett » Fri Apr 13, 2012 12:50 pm

Mike Stranks wrote:Speaker cables have to deal with many tens of volts - an amp I've just bought puts out about 40 volts onto the speakers.

More importantly, speaker cables have to deal with higher currents - possibly tens of amps if you are using speakers in parallel with a big amplifier. That's why thick cables with plenty of copper in them are better for speakers.

James.
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Re: PA Speaker connections

Postby Mike Stranks » Fri Apr 13, 2012 3:51 pm

James Perrett wrote:
Mike Stranks wrote:Speaker cables have to deal with many tens of volts - an amp I've just bought puts out about 40 volts onto the speakers.

More importantly, speaker cables have to deal with higher currents - possibly tens of amps if you are using speakers in parallel with a big amplifier. That's why thick cables with plenty of copper in them are better for speakers.

James.
See? That just proves my point about always something new to learn!
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