Bulk Cables

To many ads? Support ODJT and see no ads!
MADNESS

MADNESS

Well-Known DJ
Dec 20, 2006
2,293
49
65
Florence, AZ
www.primetimedj.net
A Musician friend of mine is creating a stage area for events on his Ramada in the mountains and he is going to hard wire cables into the walls for ease of set up and need to have less cables laying around. These will basically used for speakers and such.

He is wanting to buy bulk cable to connect to speakon connections and or 1/4 inch.

Please give me some idea where a good place to buy bulk cable (approx 1000 feet) and if there is a significant difference in the gauge. He wants to run 14 gauge.
Thanks for any help in this area you may have!!
 
For many feet of cabling I think he needs to reconsider the gauge to at least 12 and even better 10.

But if he is really set on 14 here is 1000 feet for an awesome price.

http://www.unbeatablesale.com/dh43087.html?srccode=cii_11138&cpncode=22-1075268-2

http://www.soundprotector.com/SPbulkspeaker.html

If he is going to wire his building for speakers, sound, etc. tell him to consider snake wire to supply input/output for mics line, line levels etc. the speaker wires can be connected to speakons for mains as well as subs, using NL4 connectors!
 
Scott -

We do lots, and lots of installs, so we have lots and lots of bulk cable available. There is a pretty nominal difference in price between 14 and 12 GA, particularly over 1000 ft. Are there any specific environmental needs for the cable (Plenum, etc)? Please touch base with us, I think you'll find for quality, UL rated install cable nobody can beat us. :)

Ben
 
Just a theoretical question here (I'm not a speaker/amp engineer), so work with me here. :)


Isn't it wiser, to have the amplification at the end of the chain?

Yer pumping a lot of power through those cables, from one central point. You have loss, interference, etc.

Rather than do that, move the amplification to the end point, and just run the signal inputs through the walls? Less work for the amps, lower power requirements, less chance of clipping, etc.

I recall some conversations I had with Drax on this subject, some years ago, and I ended up running my cables as I mentioned, and not pushing the amp output through the walls.

Thoughts...?
 
I think Steve Miller, Fred or Ben can better surmise this, but here's a table that might help...

My concern is not for the loss of performance, but the power draw of the amps, and interference to other stuff. It is not GREEN, to run long cable lengths from amps. And remember, I am a tree hugger :sqbiggrin:



http://www.peavey.com/support/technotes/soundsystems/longcable.cfm
 
Rick makes a good point. This is why snake cables don't offer 12 gauge Speakons for mains feed. It's why the amp racks are on stage with the speaker stacks and the soundman's console is at the mid-field or back of house. :)

Longer cable runs for mains FOH can affect damping factor. Voltage drop is also a consideration. Amps should be placed (or wired) as close to speaker systems as possible.

In the scenario you describe, it would work well if the speaker systems will be in the same place every time. If they're not, you'll still have cabling on the floor.

Thoughts?
 
Okay, Rick and Madness... you are both right here. Rick is right in practice that it is best to have the amps as close to the loudspeaker as possible. Take the Allianz arena in Munich for example... the audio is actually sent over Cat-5 (CobraNet protocol) via a redundant, self-healing network to amplifier stations near each loudspeaker cluster. In closer to home application, Fred hit it on the head by having the amp racks on stage and not at the FOH console. However, with runs of 30' I can't imagine having the amps much closer, and certainly it's not practical to have amps in 24 locations, so I think that the approach Scott's friend is taking is very pragmatic.

Ben
 
NLFX Pro said:
Okay, Rick and Madness... you are both right here. Rick is right in practice that it is best to have the amps as close to the loudspeaker as possible. Take the Allianz arena in Munich for example... the audio is actually sent over Cat-5 (CobraNet protocol) via a redundant, self-healing network to amplifier stations near each loudspeaker cluster. In closer to home application, Fred hit it on the head by having the amp racks on stage and not at the FOH console. However, with runs of 30' I can't imagine having the amps much closer, and certainly it's not practical to have amps in 24 locations, so I think that the approach Scott's friend is taking is very pragmatic.

Ben
Click to expand...


Fair enough answer Ben :)

But, you have the capability to test this -- I don't (actually I do, but I don't have quality cable to give a quality test).

Meter out the current draw of the amp with say a 30-50' foot cable, versus a 6-10 foot cable for example.

I'd be interested in seeing actual results, versus theoretical models, on how far the amps are driven, and actual output from the speakers...
 
SoftJock Rick said:
Fair enough answer Ben :)

But, you have the capability to test this -- I don't (actually I do, but I don't have quality cable to give a quality test).

Meter out the current draw of the amp with say a 30-50' foot cable, versus a 6-10 foot cable for example.

I'd be interested in seeing actual results, versus theoretical models, on how far the amps are driven, and actual output from the speakers...
Click to expand...

Ok, just so I'm clear... is the length the cable on the output side of the amplifier going to the speaker, or the AC mains supply cable? Which am I measuring the ampacity and loss on? Do you want this at full-bandwith (20-20k), or just say a 1K tone? Do you have a preference of topology (Class A/B, H, or D?)? Lastly, what wattage do you want me to put through here. I can tell you right off the top of my head that the calculation for voltage drop is directly proportional to the amperage. From memory (be nice E.Es, it's 11pm, if I'm wrong correct me gently or I'll cry), the formula is:

VD = (2 x R x I x Length) ÷ 1000

Here "R" equals the resistance in Ohms per 1000 ft as shown in the tables of the NEC and "I" represents the amperage being passed through the cable.

Ben
 
NLFX Pro said:
Ok, just so I'm clear... is the length the cable on the output side of the amplifier going to the speaker, or the AC mains supply cable? Which am I measuring the ampacity and loss on? Do you want this at full-bandwith (20-20k), or just say a 1K tone? Do you have a preference of topology (Class A/B, H, or D?)? Lastly, what wattage do you want me to put through here. I can tell you right off the top of my head that the calculation for voltage drop is directly proportional to the amperage. From memory (be nice E.Es, it's 11pm, if I'm wrong correct me gently or I'll cry), the formula is:

VD = (2 x R x I x Length) ÷ 1000

Here "R" equals the resistance in Ohms per 1000 ft as shown in the tables of the NEC and "I" represents the amperage being passed through the cable.

Ben
Click to expand...

I nominate Ben for Obama's newly created Director of Homeland Geekiness position.
 
NLFX Pro said:
... Do you have a preference of topology (Class A/B, H, or D?)?
Click to expand...
Brother Ben,

There is only one bias classification that matters with professional SR ~ that's A/B. Preferably with big, beefy Toroid power supplies and big capacitors. All the rest are toys.

Yeah, I know. I can be so unnecessary at times, lol. ;)
 
Nothing fancy Ben...

Put a meter on the amps amperage draw, using varying length cables.

I will do it here, using what cables I have, using a studio ref amp. I'll use my Samson 120, since it's handy, and I have enough cable. It's not good stuff, some Monster Cable that I have a couple spools of.

You can do a better test, I think, because you have cables already lengthed, and impedance matched.
 
In the theoretical realm, here's what we can anticipate. These are the resistance figures give in the 2005 NEC:

18 AWG copper stranded, uncoated = 7.95?*

16 AWG copper stranded, uncoated = 4.99?*

14 AWG copper stranded, uncoated = 3.14?*

12 AWG copper stranded, uncoated = 1.98?*

So, for 100 Watts using 14 AWG cable you should see a voltage drop of approximately the following:

6 feet = 0.037
10 feet = 0.062
30 feet = 0.118
50 feet = 0.314
100 feet = 0.628

If you were to substantially increase the wattage, you would also substantially increase the loss, but proportionately you can see that it's still a negligible loss between 10 feet and 30 feet.

This assumes no capacitance and a fixed frequency.

Ben
 
NLFX Pro said:
So, for 100 Watts using 14 AWG cable you should see a voltage drop of approximately the following:

6 feet = 0.037
10 feet = 0.062
30 feet = 0.118
50 feet = 0.314
100 feet = 0.628
Click to expand...

Awesome stuff.

Keep in mind that with speaker cable, there are two conductors. So a 50ft speaker cable has 100ft of wire in it.

Also keep in mind that this resistance is in addition to the load of the speaker cabinets. So, if you run a 50ft cable (100ft of wire @ 14ga) to a stack of four boxes (figure 8ohm each in parallel...so a 2ohm load), then the speaker cable will use more than 30% of the applied power.

The rule of thumb that I have used is that the cable impedance should be no more than 5% of the total impedance. To run a single 8ohm cabinet, the speaker cable could be up to 0.4ohms (that is slightly longer than a 25ft cable @14ga). To run cabinets in parallel that are 2ohms, the speaker cable should be no more than 0.1ohms (that is slightly less than a 15ft cable @ 14ga...total for connecting the farthest speaker).

In practical terms, this means to run a multiple cabinet load on an amp channel, the amp should be sitting at the bottom of the stack of speakers, and the jumpers should be as short as possible.
 
You must log in or register to reply here.
Top Bottom
Back