RMS on subs, how is it mutli. Options

[JFrost9]

Ok, so im still shopping for subs, and i assume ive figured everything out, the good brands the bad brands, the way they are measured and all the other stuff. Im still confused on one thing though. If i was to buy lets say an ALPINE SWR-1222D 12" DVC 2 Ohm 1500W SUBWOOFER. Its around 500 RMS. Heres my question... if i was to buy not 1, but 2 instead, how would that change the RMS and everything else? i thought it would just mean that i would have 1000 RMS, but that doesnt seem to be the case. Ive been searchin around to try and figure out how it works, but i figured it would be easier to ask.

[WannabeGT4]

2 DVC drivers with Voice Coils in Series / Parallel
Connecting the two voice coils of each driver in series (+ to -) and the drivers themselves in parallel (+ to +, etc.) will result in the following impedances:
Dual-6 Ohm Subwoofers: 6 Ohms
Dual-4 Ohm Subwoofer: 4 Ohms
Dual-2 Ohm Subwoofer: 2 Ohms
Dual-1.5 Ohm Subwoofer: 1.5 Ohms

If you have two dual 2 ohm voice coil subs wired in Series / Parallel the amp will be seeing a 2 ohm load. In most cases the output of the amplifier is determined by the amount of resistance it sees from the subs.

So if you have an amplifier rated at:
425W x 1 @ 4 ohms
800W x 1 @ 2 ohms
1200W x 1 @ 1 ohm
Each sub would be seeing about 400W.

But if you had an amplifier rated at:
425W x1 @ 4 ohms
850x1 @ 2 ohms
1275W x1 @ 1 ohm
Each sub would be seeing 425W. Essentially doubled.

Which is why I said it all depends on what the amplifier can provide.

EDIT: ShadowFX is right. You probably won't hear that much of a difference if you're powering two subs at 400W compared to one sub at 425W. However, if you have a more efficient amp and power them both at 425W @ 2 ohms the difference will be a bit more noticeable.

This post has been edited by WannabeGT4: Sep 14, 2005 - 9:14 AM