lets see. u run two diff size subs off a cheap crap amp. the subs aren't bad brands but u should have one size or the other. also know that amp probably doesn't put out anywhere near 800 watts lol. Another big factor in this is enclosure.....
You got a mixmatch and they don't mesh well towards a common sound output. And that amp, well it aint the worst, but it surely aint gonna blow your head off. How do you have them wired, how big of boxes, ported or sealed? how about your power wires and eletrical system?
I'm going to stick my neck out and say your boxes are sealed and too small, you have no idea what ohms are, you have a 10 guage power wire and you're pissed off at the world and want us to solve your problems. Am I close?
First thing is first. Please tell us the exact make and model of both subs, and the amplifier. (examples: MTX 6600 D4, Sony Xplod SA4002 or whatever) Tell us how you have the subs wired to the amplifier, and tell us what type of box each subwoofer is using.
With that information, I can offer some suggestions.
Think you are wasting your time glass. bogus question and bogus thread. two different kinds of subs, a notorious laughing stock amplifier brand. screams troll. if in the 1% chance it is legit, o.p. you have to many reasons to list why that setup sounds like my a** after 25 cent taco night at the local pub.
Mixing different sized and/or different drivers is akin to two people screaming at each other at the same time at a close distance - you can't measure an acoustically flat and/or clear (undistorted) sound from either person, anywhere. This is like the most basic thing in (any) audio - you say you want to hear your drivers but you're hearing two, and then wonder why you're hearing something that isn't in unison. Of every hack job I've seen in my friends' rides, the bass is always mad distorted, you can't turn it up much, and you can't distinguish between frequencies. Hella cancellation, smack yourself. I suppose I should add that a hole isn't a port - I saw that yesterday.