4 ohm dual voice sub for a 4 ohm amp
 

Hi there,

I just purchased an Alpine SWR-1242D 12" subwoofer which has dual 4 ohm voice coils and a 500W RMS. I also bought the Alpine MRP-M800 amplifier which can support 500W RMS x 1 @ 4 ohm and 800W RMS x 1 @ 2 ohm. I wanted to know how or if I need to wire it as 4 ohms as to reach the max 500W RMS. Everywhere I look it seems like is can only be wired as 2 ohms in parallel or 8 ohms in series. If anyone had some thoughts that would be great.

that is correct, it can only be wired to a 2ohm or an 8ohm load

it should be fine wiring it down to 2ohms though

So I could run the sub at 2 ohms and get 800W RMS without damaging the sub?
I would likely have to turn the gain way down..?

You should be able to get away with it. Just match your gains to the input voltage and watch your bass boost.

how do i do that...using a voltometer?
this sounds risky...what are the chances it blows the sub?

There isn't much risk. Just use a DMM to match voltage. Amps aren't 100% efficient, so your sub won't be getting 800 watts all the time. You will have enough head room to maximize your sub's potential.

alrighty then, thanks a lot scuba
i kinda wish that amp wasnt such a good deal now so i would of gotten an amp with a lower rms! haha

no problem. btw that is a great amp for you. It maximizes your sub's potential and it leaves room to upgrade in the future.

The system will generally tell you when you are over driving it (it will sound like crap) and when your ears bleed that too should indicate you are loud enough... turning down the gain is typically a good idea. The gain adjust is to balance the max output of the deck with the max output of the amplifier

It is tough to say you "wont" or "cant" damage the sub, but it is harder if you dont get crazy with the volume or gain knob

and that was a great way to say that!