Alright, I'm fairly new to the car audio deal. I bought and installed the following...

Alpine CDA-9855 Head Unit
Alpine SWR-1242D 12" Subwoofer
Alpine MRD-M605 Mono Amp

Installing it was the easy part...my question is on the hookup.

How can I match the Ohm rating for the amp/sub so it has the least possible distortion? Thanks.

 

I would hook it up 400 watts rms by 1@2ohms. look in your manuals that came with the subs and amps and there should be a wiring diragram with will show you how to wire up the subs for 2ohm between the 2 voice coils. I have the same subs but they are the 2004 model and are only 2ohm so i had to hook mine up like it showed in my manual.

 

And for being new to car audio you got some really nice stuff to start out with. You will have some fun with that head unit.

 

You'll want to wire your sub up so you have a 2ohm load on the amp. With that sub, you can have either a 2ohm load or an 8ohm load.

Take a look at this page and it will show you how to wire the sub up in parallel to get a 2ohm load:

http://www.the12volt.com/caraudio/wo...s.asp?Q=1&I=42

 

Distortion doesn't really apply to ohm rating, at least directly. (an 2 ohm setup can sound just as clean as a 1 ohm or an 18 ohm setup). Just pay attention to stability and power ratings.

Your Dual voice coil subwoofer is basically two subs in one. They can be wired in parallel (not daisy chained, but both coil's are wired straight to the amp). This will cause your amp to "see" a 2 ohm load. At 2 ohms, your amp will deliver 400 watts (probably more if you look at the "birth sheet" that comes with the amp). Your sub is rated for 500 watts, so this is well within spec. If anything you could use a more powerful amp, but 100 extra watts would barely give you 1 more dB.

 

Yes...exactly the explanation I was looking for...thanks guys...I'll let you know how it turns out.