adding more subs

hey you guys right now i have 4 12's being pushed by a jbl 1200.1 amp im gettin the full 1200 out of it. I am about to buy 4 more of the same 12's as well as another jbl 1200.1 and make another box. My question is will my new setup be twice as loud as my original setup? or is it only gonna be 3 db louder? also right now im running the 1200 watts plus a 200 watt amp for my mids and highs so like 1400 watts off the stock alternator and battery. Now that i will be getting like 2600 watts rms I am geussing i will need a ho alt. but will i need more batteries or should i just replace my stock with like a yellow top? thanks and i dont plan on running my system with out my car running so.

HO alternator is a good idea, as is a new battery.  You will see somewhere between 3 and 5db increase in your overall SPL, assuming the enclosures are the same.  If you are really after SPL, using the proper large ported enclosures can get you a lot more bang out of the 4 speakers your currently have than you get by simply adding more speakers.  The enclosure can be more important than the speakers or the amp if it's done right.  Just my opinion...

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ok so are u saying that the 4 12's i have right now in a large ported box will be louder then 8 12's sealed?

I'm saying they can be, yes.  It depends on what you're trying to accomplish.

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i want it to be louder and to where u cant breathe inside. wouldnt my new setup be roughly 6 db louder which is like twice as loud as my first setup right?

Build a ported wall, to heck with the rear of the vehicle. No breathing after that, or hearing.

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but no 6db is not twice as loud. 10 is.

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Nik
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an i hope that your not driving in thier while it is that loud u will damage your hearing. just some friendly advice

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southsider

If by chance you do damage your hearing, another 10 db should fix it, for a while.

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Nik
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in terms of the acoustic energy in the air 3dB is double, however the human ear percieves an increase of 10 fold (10dB) as roughly "twice" as loud

Definately get a HO alt no matter what you end up doing with your system, plus i also agree you should invest some time into a box program such as winisd pro and design a box for the 4 subs you have right now.  Im shure if you build a awsome box you will get the same or more volume than just adding 4 more subs.

Also invest some time into sound dampening trying to keep air and sound inside the car as much as possible.

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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

Get a high output alt (200 amps +) new batter (Optima) and tear out the rest of your car. Build a wall, put all 8 of those 12"s and stand outside of the car with a remote, or inside with a vomit bag. Two of those BP1200.1's is ungodly... i'm lovin it.

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"I don't play games. I play Nakamichi and that for real yo" - Probably some japanese kid said this in the early 80's trying to sell stereo out of his trunk lol.

lol ya my setup right now is uncomfortable so i just want it to be retarded loud. I just find it hard to believe that my 4 12's with 1200 watts can get louder then 8 12's with 2400 watts in a sealed enclosure. wouldnt i get 6 db out of the 8 12's and only around 3 if i ported the box with the 4 subs? Also would i need an extra battery of just replace my stock one with like a yellow top? im not gonna be playing it without my car on soo.

anybody?

Depends on where you port your box... There will be a peak (high Q) tuning point, where you could get as much as +12dB at one frequency... Do as DYohn suggested, download the FREE WinISD, figure it out, plug in the numbers, and build your box to do what you want it to do...


Sheesh... Kids these days. They want everybody else to do for them...

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

What kind of car is this in, wan what kind of subs are you using?? 8 subs need a hell of alot of space, even 4 need a lot of space for that matter. Also have you considered getting four better subs (maybe 15s that handle between 600-1000W apiece) and running two off each amp.

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ya i have a dodge dakota ext cab, i took out the back seats, im assure that i could fit 8 soo.Now are 15's gonna be louder as like in db wise or is it just gonna hit lower frequencies?

4 12's ported with 1200 watts or 8 12's sealed with 2400 watts. Which is going to hit harder?

Like was said before, it all depends on the ported box. You CAN make the 4 louder. Personally I'd do 8 ported.

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Nik
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lol ya i would like to port 8 but thats deff. not gonan happen in the back of my truck. So 4 ported or 8 sealed?

go with the 4 ported. It'll be about the same and cheaper.

If you wanna show it off that you have 8 subs though....

You may wanna look into building like an 8th order bandpass box. Probally too much math and too hard to construct. Gotta be dead on with it, no margin for error...

-Drew

ok ya and what would have better sound quality?

You are asking about sealed versus ported enclosures, which one will get louder... everybody tells you that ported can be louder... Now you want to know which will give better sound quality?

As was said SEVERAL times, download the free software that has been suggested, learn it, know it, live it... I don't want to be rude, but "Figure it out for yourself". Why are people content to let everybody else do all the work for them? We had to start somewhere, now it's your turn.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."