Car Stereos: Alpine Type Rs, watts rms, 4 ohms

Question
QUESTION: I have two 12" Alpine Type R's. model #SWR-1242D (4 ohms at 500 watts rms). and i am trying to find a proper amp to power these subs. should i look for rms wattage or maximum wattage? and do i want a mono amp or 2 channel?
- one amp i had in mind that i can get for cheap is this following one: Just wanted to make sure I get the right amp to push these. and the distance from the amp mount to the battery is about 13-14 feet, so would 4 gauge wire be enough to power this?
Thank you so much,
Garrett

http://vortexaudioexpress.com/store/product_info.php?manufacturers_id=11&product

ANSWER: Hi Garrett,

You want RMS power.  Ignore max wattage.  Pretend it doesn't exist.  If a salesman tells you a product's "max" wattage, slap him and ignore the number.  Max is a number made up by marketing weenies that means absolutely nothing.  RMS is what matters.

That said, you'll want either a stereo amp that can do a reasonable RMS wattage x 2 @ 4ohms, or a mono block that does a reasonable RMS wattage x 1 @ 2 ohms and run them in parallel.

The amp you listed should push them just fine.  (You don't have to match the wattage up exactly, and having the amps be a little bit less than the subs RMS is actually ideal since you know you won't overpower and blow them.)

4 gauge wire will be fine for the amp you've listed.  Make sure your ground wire is at least 4 gauge aswell, and keep it under 18" (or shorter) if possible.

---------- FOLLOW-UP ----------

QUESTION: thank you very much for your response. My only question is how would you wire both subs to run at 2 ohms? the following link shows how to wire them both in parallel, but that shows that it runs them at 1 ohm?

http://www.the12volt.com/caraudio/woofer_configurations.asp?Q=2&I=42

thank you very much!
Garrett

Answer
HI Garrett,

According to Alpine's awful website, the subwoofers are 2x4ohm coils.  I didn't know this when I first responded.

With that in mind, you'll need to either wire each sub in parallel, giving you 2x2ohm circuits (each sub), and get an amp that does a good job of 2x2ohm, or wire each sub in series, and then wire the subs themselves in parallel which will give you a 1x4ohm circuit and get an amp that does that.

(You could also wire all 4 of the coils in parallel and get a 1x1ohm circuit, or all 4 in series and get 16ohm, but that'd be rare.)

Justin