Im trying to learn about impedance and Im starting to understand but i need some help..say I have 2 4ohm DVC subs and I want to run the lowest impednace possible but I come out with a 16ohm load each time rather im using parallel or series wiring is this right..??? does each voice coil have a 4ohm impedance or does it mean that each sub has a 4ohm impedance when the manufacturer says 4ohm on the box??? each time i do the equation i use a 4ohm load for each voice coil..is this right???
Nope, that's not right, you've got the equations mixed up. When you wire in series, you add the impedance of all the voice coils. For parallel, it's a little more complicated. The equation is 1/Rt=1/r1 + 1/r2 + 1/r3....etc. rt is total resistance, r1 is voice coil 1's impedance, etc. Anyway, in your case, it'll be 1/rt = 1/4 + 1/4 + 1/4 + 1/4, so then 1/rt=4/4. You cross-multiply after that, so it'll be 4 = 4rt Anyway, eventually you get a 1 ohm load.
If you're curious, the reason for the equation being like that, when you wire in parallel, you're increasing the amount of paths that current can flow, which decreases resistance because current has more places to go. Similar to if you had two water lines as opposed to one for the same amount of water flowing. The impedance of the voice coils remains the same, but the load presented to the amp is lessened because there are more paths for current flow.