going from 1 sub, amp and cap, to two

Hey guys and gals,

I currently have 1 audiobahn alum12q sub, an A8000T amplifier, and a 1 farad capacitor, all audiobahn. I recently got a complete duplicate of what i have now, so another sub, amp and cap, all the exact same. the first set is all wired and working, and i have a few questions about adding the second set.

First question: on the already installed amp, can i just run another rca type cable to the other amp, or do i have to get a new headunit with two preouts?

Second question: do i have to run another set of power cables from the battery, or do i go from one cap, to the amp, and to the other cap then to the amp that goes with that cap?

Third question: can i build another single sub box and add it to the one i have (basically right next to it), or should i build another box that holds both of them without seperation?

Fourth question: I get some pretty bad vibration from the trunk lid and some black plastic piece under the rear bumper of the caddy. is there anything else i could do besides adding that sound deadning paper/sticky stuff?

Thanks for the help in advance guys and gals.

1) You can split the RCAs, or if your amp has outs as well, I would recommend tapping on that. This will also depend on what head unit you have too since splitting them will split the quality to each amp. If your source outputs at least 2 volts then you shouldn't have to worry about it, 4 volts or better is don't need to worry about it. 6 volts and higher, "why do you only have 2 amps then???" ^-^

2) That will depend on what wiring you have now... Assuing you are running 4 guage right now you'll have two options: a] run another set of 4 guage wiring for the new pieces and, b] upgrade your wiring to 0 guage for the lead wire and split that through a 0-4x2 fused distribution block. Then to each of their respective equipment.

3) Since there will be two amps (1 per sub), I would recommend either making a second box, or make a single box with a partition for the subs. I do not recommend a common box. If the amps are not gain-matched properly, then one sub can apply overpressure to the other sub and both can be potentially damaged.

4) Reinforce and strengthen the areas in question. For trunk lids, you can have the struts fully welded along the whole area for example. If the piece rattles, lock it down. Other than that, I can't think of anything else really... besides Dynamat, etc...

Ganbatte ne!

Alright, sounds great so far and thanks for the help. I wanna say im currently running zero gauge wire from the battery back (its about the size of my pinky/smallest finger). What exactly is a "0-4x2 fused distribution block"? could i  get one on ebay? i originally got a wiring kit when i first installed the kit, and in the directions it said to mount this box looking thing with two fuses in it right next to the batter, is this what your referring to?

anymore help would be greatly appreciated, seeing as im kind of new to the whole audio installing. This is my first install, but im pretty happy with it.

Thanks agian guys and gals