Bass keeps going soft then hard

[GQNammer]

K, I dunno how to word this right, but when I drive, 70% of the time my bass sounds more quiet than the other 30% of the time. I will be driving for 5 min and the bass to me sounds normal. Then all of the sudden, my bass will start to hit harder than earlier and it sounds awesome. What's wrong with my bass? I have 2 10'' Type Rs with an alpine MRD-1000 amp. I also have a cap.

[EarthWake_Audio]

the MRDM1000 is a great amp(if you are running it at 2 ohms)
i think your problem would have to do with heat issues caused by running the amp at 1 ohm...i have seen it a thousand times...
are your subs dual 4 ohm or dual 2 ohm drivers?

i bet that is the issue

[BumpinTalon]

I'd say its the amp going into and out of thermal protection. either disable it somehow, or rewire your subs.