Audio Systems: cap use, kicker subs, farad cap

Question
in terms of using more speakers you are recomending that i would be better off to get a 3rd L5 i need a balance of real loud and still being able to youse the trunk space i think if i added two more a new box would just have to bee to large, if i do three what is the wiring recomendation.  the only reason i only have 2 is i was told it takes alot of power to get thos square kicker subs to hit, so i was worried about adding a third sub.  i think they are rated to handle 600 watts
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Followup To
Question -
i have an audiobahn 1600 watt amp running to two kicker 12' L5's my problem is my lights continue to dim.  i purchased a one fraud cap and it solved the problem, until had to switch out the amp for a new one audiobahn sent me same wattage.  I hooked up the amp and have had problems ever since, do i need to recharge the cap or what have never really understood the instaltion of the cap so i left a shop do it.
Answer -
Sounds like your amp levels are too high or the alternator is not large enough to carry the load.
I ran two 18's from a 300 RMS watt amp in my car (VW-GTi 16v), it yielded over 142Db (A wieghted) with ZERO clipping.
How loud do you NEED it, my friend?

Those that are after massive SPL, would likely use sixteen 12's and a 1000 watt amp. This is why:

Double your power and the output goes up about 3db..
Double the amount of speakers and the output goes up 6db.. (equal to quadruppling the power and the fact that speakers are much cheaper than amplifiers is only more testimony to this resolve).

A one Farad cap is pretty simple to install if you understand series and parallel 12v systems. However, most pros would recommend 1 farad per 500-1000 watts of RMS power. Some extremists use 1 farad per 100 watts.

The caps' positive post goes in series with the 12v power supply wire. That is, the 12v line will come to the positive post, then continue on to the power distribution for the amp(s).
The ground gets grounded to the vehicle chassis.

JM


Answer
Generally speaking...Perhaps.
But, that is another major aspect, the efficiency of the speaker used (when considering average and peak SPL).
Simply put, if a speaker required that much power to get adequately loud, I would not choose it. I used C-18" Kickers in a very efficient dual sealed array in my GTi (Which put my 1 watt subwoofer level at about 109 db). I knew I did not need 1000 watts each (their RMS rating each) to power them to a more than accurate level. I do Like Kickers for the money. For accuracy and longevity, I prefer the extended low end of Sealed enclosures over a ported ones' "boom note" anyday. I listened to about any type of music you can imagine. But mostly, I designed the system from the get-go to be efficient and smooth throughout the freqs and choose a 300 watt amp which I ran at 4 ohms mono for a 450 watt RMS (or 225 wrms to each 18) load. They hit like Tyson as it was but they would have crushed anyones brain at full RMS power.
Its all relative to what you want and like (and the space and money you have available).

You can pre-determine much of this if you have the specs and the know-how.
Remember that displacement is as important as todays' super long-throw speaker excursions. For instance, you might fair much better using  four 10's or 12's in a sealed array, ect.

Hope this helps

Jm