Which wire gauge for a far away sub?

hi,

this has been about posted before...use this to help

http://www.h-o-alternators.com/TechCalcs/speakerwireselectorassistanthoalt.swf

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The above mentioned group of calculators are handy...everyone should save them to file.  The basic way to find how much amperage could possibly be carried through a wire so that you can select the proper wire gauge is to use Ohm's Law.  Use two known factors to find the third.

In this case you know the power output of the amp and you know the impedance load that this output is going into.  So to find current use I = SQR(P/R).  If the impedance load is 2 ohms and you know that the amp may output 600 watts, the current would be 17.3 amps.  Peaks in the output would not have to be considered because if they occur at all they would be very short durations.

With 17.3 amps as your current, consult a wire gauge like those listed on this site (linked above by dwarren).  The chart shows that 16 guage is good to 15 amps, so you could step up to 14 gauge.  Mind you, the vast majority of the time the current will be well under 15 amps, so 16 ga. is what I would use if it were me.  But just for the sake of being detail-oriented, the chart says to go to 14 gauge.

Using a beefier wire like 14 gauge, you wouldn't need to worry about the run length.  But if you were to use 16 ga. you might also look at loss that could occur if your wire gets to be on the long side.  You can see by using the calculator (linked above by Ween) that the loss with the smaller 16 ga. wire would be minimal on a 10' run (only losing 1/3  db)...so using 16 ga. would be fine in any event.  Whatever wire you have on hand...

But if by chance you're running the amp at 1 ohm, you'll see a greater current and more of a reason to use 14 ga. speaker wire.

Damn right I do! You can never go too big.

Damn, that was a late night post, what was I thinking. I thought those were a little off