speaker wire gauge

[JustinBrown]

i have to run a sound system around a 50 meter pool. i don't know how many feet exactly, but i am assuming ~200.

what gauge wire should i use? i read somewhere online that anything over 50ft should be 12AWG. is this correct?

i have a Bogen 250W amp going to eight 20W speakers.

thanks for your help.

 

[markw]

I have a Bogen 250W amp going to eight 20W speakers.

Depending on several things, 10 gauge might work for a run of 200 feet.

How do you have these 20 speakers wired to the amp?

More : http://www.roger-russell.com/wire/wire.htm#wiretable

 

[JustinBrown]

12 guage should be fine.

How do you have these 20 speakers wired to the amp?

do i need 12 or could i get away with a smaller cable?

i daisy chained the speakers on 70V. is that the best way? should i use 8 ohm? there are only eight speakers, but 20W.

 

[MinusTheBear]

What lengths will you be running to each speaker. Depending on the lengths 10 awg might be a good choice.

 

[markw]

I edited my post.

My post was assuming "normsl" (non-70 volt) configuration

70 volts will essentially "up" the effective impedance but I don't know how much and how this will affect the wire guage.

How many speakers did you say you're running? 20 or 8?

edit: never mind. I see where I got that 20 from.

 

[JustinBrown]

My post was assuming "normsl" (non-70 volt) configuration

70 volts will essentially "up" the effective impedance but I don't know how much and how this will affect the wire guage.

How many speakers did you say you're running? 20 or 8?

i have 8 speakers. they are 20 watt each.

should i not be using 70 volt, or is that the best way to do it?

is 12 gauge the smallest i can go, or could i get away with 14?

 

[markw]

If you're daisy chaining them you really have no option except 70 volts.

I'll bow out at this point.

 

[Midcow2]

16 gauge should work okay for 200ft.

i have to run a sound system around a 50 meter pool. i don't know how many feet exactly, but i am assuming ~200.

what gauge wire should i use? i read somewhere online that anything over 50ft should be 12AWG. is this correct?

i have a Bogen 250W amp going to eight 20W speakers.

thanks for your help.

You can get by with a smaller wire.
Here is a table I built for you:

Wire Gauge Resistance /Ft. 200ft % to 8 ohm
4...................... 0.000292.............0.093..... 1.8%
6...................... 0.000465.............0.1478.... 2.9%
8...................... 0.000739.............0.236..... 4.5%
10...................... 0.00118............. 0.374..... 6.9%
12...................... 0.00187............. 0.594..... 10.6%
14...................... 0.00297............. 0.946..... 15.8%
16...................... 0.00473..............1.502..... 22.9%
18...................... 0.00751...............2.38...... 32.2%
20...................... 0.0119................. 3.8...... 43.0%

You could porbably get by with 14 gauge or even 16 gauge. Using 16 gauge fro a 200 foot run the wire itself would have a resistance of 1.502 ohms which means 22.9 % of your power would be lost through the wire into 8 ohm speakers.

22.9% = (1.502 / (1.502 +8)

 

[mtrycrafts]

Don't forget, he has that 200ft one way and another 200ft the other way coming back, 400ft of resistance.

 

[Rickster71]

Most commercial systems require 18 gauge 2 conductor without a shield.
Here is some actual math: 1 watt at 70 volts means that you have 5000 Ohms Impedance. The transformer / speaker combination that's used measures about 5000 ohms on the 1 watt tap. If we selected the 2 watt tap the impedance would go down to 2500 ohms etc. With this high of a load impedance, the wire loss due to resistance between speakers on relatively small wire is negligible. Wire size of AWG 18 is adequate for small and even large 70 volt projects.

 

[annunaki]

Most commercial systems require 18 gauge 2 conductor without a shield.
Here is some actual math: 1 watt at 70 volts means that you have 5000 Ohms Impedance. The transformer / speaker combination that's used measures about 5000 ohms on the 1 watt tap. If we selected the 2 watt tap the impedance would go down to 2500 ohms etc. With this high of a load impedance, the wire loss due to resistance between speakers on relatively small wire is negligible. Wire size of AWG 18 is adequate for small and even large 70 volt projects.

Rickster is right on here.

With a 70volt application, 12 awg is complete overkill. 14 awg. is overkill as well in this application.

16 awg. would be good piece of mind and allow plenty of signal/power flow.

 

[Rickster71]

If your plans are to run the speaker wires in the landscaping around the pool.
I'd suggest using thin low voltage landscape wiring from the Depot or Loews.
It's direct burial wire; and works very well it that type of application.
As annunaki says, 16AWG would work well.