Car Stereos: subwoofer/amps, ohm voice coils, dual voice coil

Question
Hello, I have a quick question to ask you. I have a alpine mrd-m501 mono block amp that has a 550 rms watt @ 2ohms and 275rms watts @ 4, i was wondering will this be a bad idea to have this sub with it, Almani S7 Series 10 1000 watt rms and the impedances can be 1,2, or 4 ohms thanks. the reason i ask is because is it bad to have an amp that is under power? thanks

Answer
Hi Ben,

I'm not personally familiar with the Almani subwoofer, and I couldn't get to any useful support documentation on their web site, so I'm not certain how you can select 1,2,or 4 ohms.  Generally, a dual voice coil sub will have either 4-ohm or 2-ohm voice coils.  A dual 4-ohm sub can be wired for a 2-ohm or 8-ohm load, and a dual 2-ohm sub can be wired for 1-ohm or 4-ohm.  Obviously, the best option for your amp would be a dual 4-ohm sub wired in a 2-ohm configuration.

In general, there's no problem with using an amplifier that's rated lower than the subwoofer's RMS power rating.  The power rating of a speaker or subwoofer is meant to specify the maximum continuous power that the sub can handle without suffering damage from overheating.  Driving the sub with a lower power level won't hurt a bit; you just won't be able to get to the subs' maximum power output.  For a 1000-watt RMS subwoofer, 550 watts RMS is a perfectly acceptable level of power.  Even if you have the full 1000 watts available, the sub wouldn't play twice as loud; you'd probably get just under 3dB of additional output.  

To sum up, I think your amp will work well with your subwoofer, even though it doesn't match the sub's RMS power rating.

Hope this helps!

Brian