Car Stereos: Amp Overheating, soundstream rubicon, kicker solobaric

Question
I have two Soundstream Rubicon amps. 1: 2.250 pushing MB Quart 6 1/2 components and 1: 1.700 on a Kicker Solobaric 12L5 4ohm DVC. It is wired to run at 2ohms. The amps are mounted on the back of my seats in the trunk. They are supplied by 4ga wire (each straight from the battery) and they each have their own 4 ga ground roughly 10" from the amp. Both amps get HOT. REAL HOT. The sub amp cut off for the first time two days ago after playing for about an hour an a half. The gain was set just past half way (about 5-10 degrees). The bass boost was set to +6. My remote gain was set to half way and the subwoofer volume on my head unit was varying between +9 and +11. My question is this: should I get a smaller sub? Say a Solobaric 10? I have turned the bass boost off and turned the gain down to a little under half way and will be driving back home today (road trip!) so I will be playing the system at loud volumes again for a long period of time. Oh yes, my alternator is putting out between 14.2-14.4 volts continuous.

Answer
Hi Jason,

Sorry about the delay in answering your question.

It's not unusual for amplifiers to get quite hot, especially class AB amps like yours.  If they're going into a thermal "protect" mode, then it's a problem.  Switching to a smaller subwoofer, though, won't really help; the heat is being produced by high current, and the characteristic of the sub that affects the current flow is the impedance.  In other words, the amplifier's likely to get just as hot with a 10" sub as a 15" sub, provided they're both 2 ohms.  If you switch to a sub that can be wired as a 4-ohm load, that should reduce the current flow and the heat buildup; of course, it will also reduce the power output.

Without seeing the setup, I don't really have any good suggestions for helping reduce the heat buildup.  Just try to make sure there's plenty of breathing room around the amplifiers.  One thing you can try: if the amps are mounted flat to the seat, you can try putting in spacers to make a gap between the back of the seat and the back of the amplifier.  Opening up some space for air flow at the back of the amp might help cool it off a bit.

Switching to a different subwoofer amp, like the 1.800, would probably help.  The 1.800 has a 2-ohm power rating pretty close to the 1.700, but it's a class D amplifier.  These tend to be more efficient, and don't produce as much heat.

Hope this helps!

Brian