Speaker cable runs - how far?

[Danno13]

Hoping someone can help with this....

How far is it possible to run speaker cables without experiencing a significant loss? Is there any way to calculate how much you'd loose? I expect diamter of cables would be a factor and possibly some specification on the amp as well?

[theoloyla]

The thicker the cable the further you can run it.

[Danno13]

Yep.. thats what I thought, but I was after some real measurements for say 2mm or 4mm cable - how far is too far? 30m? 50m? 150m? Oh.. and run at 4ohms most probably.

[TonyB]

This page may help http://www.roger-russell.com/wire/wire.htm.

It depends on the thickness of the wire but the maximum with the thickest wire seems to be 50ft.

[Danno13]

Thanks Tony, useful info there.. although I can't work out how the AWG rating coresponds to the diameter of the cable.. the Wiki article on it just confused me even more!

Oh, hang on.. I think i've got it 3mm^2 cable is roughly 12AWG and 1.5mm^2 cable is around 6AWG.. although that makes no sense, as according to the table on the link you posted, the lower the AWG the longer the run can be!

[jimboylan]

As the AWG goes lower the mm2 goes higher.
Table here (http://www.technick.net/public/code/cp_dpage.php?aiocp_dp=guide_awg_to_metric)

Jim

[Andy Westcott]

Also, if you can run at 8 ohms the losses will be a lot less. And if you can run into 16 ohms, even better.

What exactly is it you wish to do?

[Danno13]

Its for PA at an outdoor fete.

[Andy Westcott]

To be completely realistic, if you are using 2.5mm CSA wire, you can run it pretty much as far as you like within reason.

There will be some slight power loss, and less of what we call 'damping factor' due to the cable's resistance, but in this application I really don't think that matters - no-one is going to expect hi-fi standards of bass control.

As an example, if the total cable resistance measured a whopping 4 ohms (that'd be a pretty long run) the speaker's output (assuming it was a 4 ohm unit) would drop by about 6dB - hardly earth-shattering in outdoor PA terms. An 8 ohm unit would drop less than this.

Go for it, and don't worry about it - it isn't a big issue. Just have a reasonably powerful amplifier so you can shove some decent voltage down the line to allow for the slight drop.

[Danno13]

Cheers Andy,

It's most probably going to be in 4ohm and I'll run two speakers on each side of the amp, one about 20m away, then another as far aware as I can manage! Would it be a good idea to wire them in parallel to get 16ohm instead? Or would the benefits be counteracted by the fact the amp will supply less power?

Channels of amp power avaliable are 4 x 400w (8ohm) 2 x 250w (8ohm) and 2 x 450w (8ohm).

[djdarren]

i once did a 25m run with some 2 core 6a mains cable... cant say i noticed any loss.

since its just a fate i expect its just background music and occational speach so i cant see there being a problem.

[Jaggiebunnett]

2.5 mm is the same as the 12 awg or "#12" so you can go from there on the chart (60 ft @ 4ohm):) :)

[Danno13]

Well, in the end I must have had a good 100m+ on each side of the field, even chopped up a 20m extension reel for part of it! Then another 40m to a speaker in the car park and a couple of metres up to a speaker which I stuck on the roof of the van.

Was running 2kw to each side of the field and 450w to each of the other cabs and had masses of headroom, music and announcments were clear throughout the whole field, so job done! Have masses of speaker cable ready for next year and any other similar jobs now too.

[501damian501]

thats good then plenty of spare cabling :D

[DJWilson]

Looks good, IMO then speakers llok to tall on them tirpods, doesnt look to safe to me but thats IMO.

[501damian501]

they have to be tall to get the sound waves across :D

[501damian501]

i think what you need is active speakers and a wireless phono to phono system, i once saw an wireless phono system on the internet, but i have forgotten the link, i will try and track it down for you, cheers damian

[501damian501]

here is a basic verison of what i mean http://www.amazon.co.uk/ROSS-Wireless-Audio-Sender-AUSN864-RO/dp/B0012MGKNQ cheers damian

[djsteve10]

Looks good, IMO then speakers llok to tall on them tirpods, doesnt look to safe to me but thats IMO.

The speakers are high up to disperse the sound and give plenty of coverage rather than have them low and the sound to be absorbed by objects in the way.

[rob1963]

I believe you need a lot of power for outside events like fetes or sports days, partly because you have to cover a much larger area than your average disco, and partly because there are no walls for the sound to bounce off.

[ppentertainments]

I believe you need a lot of power for outside events like fetes or sports days, partly because you have to cover a much larger area than your average disco, and partly because there are no walls for the sound to bounce off.

Very true but also factors such as wind direction makes a very big difference. If the wind is blowing in the right direction it helps a lot.

I use a 2.6kw system for outside functions (firework displays, carnivals etc) which is too loud sometimes and not loud enough at other times with the wind being the deciding factor.

[Tom]

Dan, what is the blue piece of equipment in your rack box???

[djdarch]

its an amplifier a powersoft nice bit of kit!

[Danno13]

Yup its a Powersoft Q4002.

Damian.. the gig was the Saturday just gone, but thanks for the suggestion anyway. Using powered speakers really wasn't an option due to the weather and likelyhood of rain, and decent reliable radio transmitters cost a fortune. I've used the cheap ones and really wouldn't bother over the distance needed for this event.