How much power is each voice coil getting?

Question

If I had an mono block amp that pushes 500 watts at 2 ohms and I wired a dual four ohm sub in parralell would each coil be getting 500 watts or would the wattage split to 250 watts per coil?

Answer 1

It splits. 250 + 250 = 500

Answer 2

Each coil would get 250 watts. In a parallel circuit with two identical impedances, voltage is the same for both but the current is split evenly between the two. Since power is the product of voltage and current, cutting current in half cuts the power in half. Here's the math:

Voltage at the speaker terminals, 500 watts into 2 ohms:
E (voltage) = SQRT(P*R)
E = SQRT(500 * 2)
E = 31.62 volts

Current at the speaker terminals:
I (current) = E/R
I = 31.62 / 2
I = 15.81 amps

Current in each voice coil:
I = E/R
I = 31.62 / 4
I = 7.91 amps

Power in each voice coil:
P = IE
P = 31.62 * 7.91
P = 250.11 watts
(Our final answer is slightly off because of rounding in the various equations).

Note that the answer and logic would be the same if you were talking about two single voice coil subwoofers, instead of one dual voice coil sub.

I know that's probably WAAAY more of an answer than you wanted but if you're interested in car audio, a complete understanding of Ohm's Law makes things much clearer.
Here's a useful link: http://www.the12volt.com/ohm/ohmslaw.asp

Answer 3

the sub is getting 500watts total , even though its a dual voice coil its not really splitting off anywhere so it dosent matter you could say that each coil is getting 250watts if you want, but like i said it dosent really matter

Answer 4

http://www.rockfordfosgate.com/rftech/woofer_wizard.asp