Expert: Cleggsan - 9/15/2009

Question
I have a Rockford Fosgate 12" Punch Subwoofer in a sealed box and I don't know what kind or size amp to get for it I have read that I should get more watts than the rms rating but I'm not sure how much more to get.I have a '87 Ford Bronco  

Answer
First, pay no attention to the power ratings of speakers as they don't mean a whole lot.  They are primarily advertising propaganda.  Most important specs are impedance ratings and sensitivity.

Sensitivity is medium to low at 85db on this series and impedance is 2 ohm dual voice coil. Since it is already mounted in a box you need to know the internal wiring for final impedance.  sometimes there is a switch to make it either 1 ohm or 4 ohms.  But, in either case, the impedance loading on the amplifier should be equal or greater than the rating of the amplifier.  

Power is up to you.  If you want lots of bass output you will need a big amp.  But, if you go too big for the Bronco you will need a heavy duty battery or a heavy duty alternator or both.  Therefore, you will need to be careful in choosing the amplifier to stay within the electrical system of the Bronco.  A Class D amp might be the best since they draw less current from the car battery than AB amps do.  

If you are confused, let me know your further questions.

C