what is causing the overload?

Have a 94 accord 4D
started noticing the problem when i listen to my radio the thing would shut off then start again less power full
have aftermarket head lights+tail lights
2amps and 2sub 4sony speakers

my battery keeps draining but once i jump start the car the battery is fine until i turn it off and will not start
saw the altenator looking old so replaced it with a drand new one
then the same thing still happens when i listen to my radio
but the battery does not get drained
so i thought due 2 the old battery went through so much let me replace it went to discount auto and bought a new battery thats more powerfull then the original silver star had in there but right after putting it the radio still does the same thing shuts off for 2 secs then comes back less powerfull
so i tested the battery there and with the car ON there is negative 30amps (does fluctuate 21-30) on the battery everything turned off (radio, air,lights, everything... that i can think off) so i was told by them with the car ON the altenator is suppose to keep the battery on +amp but we know the altenator is working fine because it was just replaced (less than a week ago and soveld the problem with the car not starting) so there is something draining the thing what can it be, ??????
please help

My first thought is does the problem exist when you leave the stereo turned off? Or, is this a problem that only happens when you have the stereo on? What happens to your guage when you have the stereo off? Does it go back to the positive side of the guage? Or does the guage stay negative even when the stereo is off? If your guage goes from positive to negative readings when you pump up the stereo then your alternator isn't charging fast enough to keep up with the demands of your amplifiers. If you already know for sure it isn't the stereo then you might want to start pulling fuses, one at a time, and see if you can narrow down the circuit that is causing the drain.