what gauge of speaker cable should I use for a 25 meter run

[pilgrim]

I am running a few long speaker cable up to 25m for a PA system, so FOH / monitors / drumfills - I understand that for around a 10m run - a 2.5mm cable has around a 3% per cent power loss - but at 25m that goes up to around 9%. Could anyone recommend what thinkness would be best for around just a 3.5% loss of power over 25m. Also – does anybody know a good supplier that could do 100m reels – at a good price - london / uk. Any names of suppliers or make of cable would be great. – will be using a passive system - with 4 pole speakon connectors. Thanks in advance - pilgrim

[ChazHS]

Problably best to use some 4mm, although you will struggle to effectively fit 4 of them in a speakon, it's tricky enough with two of the 4mm cables! Can you not place the amplifier racks closer to the FOH? Or are the speakers being flown?

 

In terms of manufacturers, VDC are probably one of the best. Failing you don't have a trade account with any sound suppliers then Thomann would probably be best. I have some of their Cordial speaker cable and have to say I'm impressed with it (although its 4 x 2.5 rather than 4 x 4!)

[Dave]

The power loss isn't fixed - it depends on the speaker impedance - you'll get more loss running into 4 ohm speakers than you will into 8 ohm speakers. Also bear in mind that quoted loudspeaker impedances are just rough averages as they vary according to frequency (ie style of music etc).

 

If you tell us the impedance of your speakers (it would be interesting to know the make/model as well) one of us will do some sums if we're feeling keen (I'm not at the moment!).

 

Most PA companies use 2.5mm cable and I personally wouldn't worry too much about losses over a 25m run. The next size up is 4mm, and you may be able to get a 6mm cable if you look hard enough. 4mm is around twice the price and twice the weight of 2.5mm, as well as being thicker, and few bother with it.

 

Van Damme cable (from www.vdctrading.com) is very popular and not that dear if you get trade pricing. But to be honest, again, few people worry too much about their speaker cable - you see other makes used (the cheapo stuff from Studiospares is perfectly OK), as well as YY and H07 main cable.

 

EDIT: Someone beat me to it! Just to add that you can, with care, get 4 x 4mm in a speakon - you need to consider what order you put the cores in, though. I was a little confused by the original post as it mentioned both 4 pole speakons and a passive system. I suspect that two core cable may be all that's needed, wired into four pole speakons, which is a common practice - the two pole speakons aren't that popular.

[paulears]

4 x 4mm works well at one end, but I always have problems with the other end, when the core lay is wrong!

[ChazHS]

4 x 4mm works well at one end, but I always have problems with the other end, when the core lay is wrong!

 

Tell me about it, thats why I opted for 4 x 2.5 rather than 4 x 4, my 2.5mm only goes up to runs of 12.5 meters anyway. If I want more I have some 2 x 4mm to run. Means two needed for the same as 2.5mm cable, but 90% of the time my amp racks arnt far from the speakers anyway!

[djandydee]

but at 25m that goes up to around 9%.

 

9% equates to 0.5 db - not many people even in the audio department here in TV land can hear that.

 

I suppose it does screw with damping factor though. Rob?

[Sound Juice]

I've never found the losses to be a problem even on 35m and 50m runs, so I don't think you'll need to worry unless your having an audiophile moment?

[rooftop]

The Neutrik NLT4FX speakon connector is useful for 4x4mm cable as it is will accomodate 6mm cable.

[Pyramid]

You can get 2 core 6mm HO7 in a standard 4 pole speakon, just take out the screws and clamps/crimps and soler straight into the buckets. We have done this with cables for our subs.

 

I am fairly sure that I also did this with 4core 4mm HO7, can't remember whether we neeeded to solder or if the clamps were ok?

 

Having said that, the losses are 25m are normally nothing to worry about.

 

Andy

[Dave]

4 x 4mm works well at one end, but I always have problems with the other end, when the core lay is wrong!

If you don't know, the trick is to arrange it so that at the "other" end, the cores for 1+ and 2+ cross over. You may have to ignore any coding on the cores to get this to work, but it can be done.

 

I forgot about the NLT4FX, despite the fact I have a few of them. Definitely the best (but also heaviest and dearest) for large cables. If only this had been available when the speakon was launched, with both sexes in cable and panel versions, then we wouldn't have the couplers to worry about.

[Paul J Need]

2.5mm will be perfect - unless you want to take out a small mortgage for the price difference of 4mm - also do you really want to be humping a 25m 4mm cable around site ( flamin' heavy)

 

You'd probably need to fill out a 12 page RA just for the movement of said cable (joke)

 

If you need them made up just give us a bell

 

Paul

[paulears]

If you don't know, the trick is to arrange it so that at the "other" end, the cores for 1+ and 2+ cross over. You may have to ignore any coding on the cores to get this to work, but it can be done.

This is what I mean - it's crossing over the two cores that takes up the limited space in the connector. I don't understand what you mean about ignoring the coding though? whatever you do, you have to solve the mirror image problem, but the 1+ still has to go to the 1+?

[bruce]

I read it as... If you wire one end "with the lay" of the cable - ie no twists - you'll end up having to have 2 pairs twisted at the other end, which is awkward. However, if when making up the first end, you add a twist there, you would end up with 1 twist at each end, rather than 2 twists in one connector.

 

That was difficult to explain!

[pilgrim]

The power loss isn't fixed - it depends on the speaker impedance - you'll get more loss running into 4 ohm speakers than you will into 8 ohm speakers. Also bear in mind that quoted loudspeaker impedances are just rough averages as they vary according to frequency (ie style of music etc).

 

If you tell us the impedance of your speakers (it would be interesting to know the make/model as well) one of us will do some sums if we're feeling keen (I'm not at the moment!).

 

Most PA companies use 2.5mm cable and I personally wouldn't worry too much about losses over a 25m run. The next size up is 4mm, and you may be able to get a 6mm cable if you look hard enough. 4mm is around twice the price and twice the weight of 2.5mm, as well as being thicker, and few bother with it.

 

Van Damme cable (from www.vdctrading.com) is very popular and not that dear if you get trade pricing. But to be honest, again, few people worry too much about their speaker cable - you see other makes used (the cheapo stuff from Studiospares is perfectly OK), as well as YY and H07 main cable.

 

EDIT: Someone beat me to it! Just to add that you can, with care, get 4 x 4mm in a speakon - you need to consider what order you put the cores in, though. I was a little confused by the original post as it mentioned both 4 pole speakons and a passive system. I suspect that two core cable may be all that's needed, wired into four pole speakons, which is a common practice - the two pole speakons aren't that popular.

[paulears]

Thanks Bruce - a single twist at either end - makes a lot of sense. Thanks for that.