Well i went out and bought an optima yellowtop today, which was a waste of F@!#%&* money because it didnt help the voltage drop whatsoever. Now my question is that if i get a 200 amp alternator will i still need to have another battery in the trunk.

Without knowing what you have that'* sucking the power that hard... it'* tough to say.

Yep, give us the juicy details and we can better help you.

Also you have to understand that the alternator provides more flowing power, while the battery provides more storage. Adding a battery does not add to your voltage, just storage.

Generally people with big audio systems will have second batteries for two reasons:
1: So they don't kill the main battery while the engine isn't running
2: The second battery is a performance battery that can charge/discharge quicker thus helping to hold the voltage up during heavy bass or power draw.

With the alternator (and some bigger power wiring all around) you will alleviate voltage drop and dimming lights. With the battery you will allow the system to run longer without running out of juice and also with a performance audio battery you will be able to better sustain those moments of heavy draw.

To the OP, have you upgraded your wiring under the hood? There are 3-5 wires that people generally always upgrade because they're way too small from the factory for aftermarket sound systems.

I have an alpine mrp-m2000 which according to the birth sheet does 2,100 rms at 2 ohms which is how i have the subs wired. I have all 0 gauge including the big three upgrade, and the optima battery.And my voltage will go well into the red zone when it hits hard.

You said Big 3. Which big 3. There are actually 5 that I usually upgrade when I do the job.

Also, if you have the stock alt, which I assume is 105 amps, that'* good for 1260 watts at 12V at max alternator load, at max alternator RPM. Now is that 2100W RMS rating at 12V, 14V, 15V? I've seen a number of ratings for amps, and that changes things.

What kind of Optima battery did you buy? Is it an extra battery, or a replacement for the original?

Does the amp give you a power requirement rating?

Sounds like it gets pretty thirsty while going deaf.

2,100 watts at 14.4 volts, and when i did the big three it would stay at 14.6 volts in park. But its been about two months since ive done that and now it will be at 14 when i start it and then once i start driving it will just stay around 13 and wont go any higher.

try the alt sense wire mod and check your amp ground in the trunk.

what could be wrong with the ground that would cause the problem. Its a secure ground but i never did remove the paint from the bolt area.