DtaWat

I have 2 12in LE audio subs and 1 15in JL audio sub. I heard of people putting subs under their seats instead of the trunk.. Would that be possible for an 03 2dr civic ex?

Kennykid2002

iTrader: (1)

In short, No, Most large subwoofers, especially JL Audio's cannot live without a box with a certain amount of cubic inches.

If you're looking at under seat subwoofer, you're prolly looking for a powered sub around 8"

DtaWat

Would it be possible to put the 2 12's in the rear deck?

Kennykid2002

iTrader: (1)

Nope, not without cutting into the sheet metal, and customization of the panels

The rear decks are designed to hold 6x9's

If you want the trunk space, I would advise you the best route is to create a custom box that fits in the spare tire well. (down side, obviously is that you'd lose your spare tire)

DtaWat

I'm not really worried about trunk space, I just want better sound.

Kennykid2002

iTrader: (1)

Trust me, if you can fit that 1 15" in your trunk, you dont have to worry about sound

What i'd do is remove your rear 6x9's to create a "port", sort of to move the air better.
Or put the 2 12"s in a ported box, and remove 6x9's

I have 1 12" in my 03 coupe trunk and its more than enough

DtaWat

Would it sound alright to put the 2 12s and the 15 in a ported box in the trunk?

Kennykid2002

iTrader: (1)

I wouldnt advise mix and matching subs

DtaWat

Alright, thanks. Just curious, why?

whitecivic2003

getting proper sound is about making everything work together. but do not mix subs it cases cancellation. the subs must be put in boxes that are the correct air space for them . and the amp must have enough power to move the subs and proper crossover cut offs if the head unit doesn't already . the head unit has to provide a clean signal with a high enough voltage output. the main problem is people think that there is just one magic component to making good sound . but its about making it it work together.

whitecivic2003

cancellation explained= the different size subs move at a different rate than each other so lets just say that when the 12s are on the way out the 15 is on the way in so the compression of the air is lost reducing the pressure level in the car .

DtaWat

Alright, I guess I will be selling my 15.

Thanks guys I appreciate the help.

whitecivic2003

what series 15 is it and what amp do you have ? i used to work for jl audio
what music do you listen to

DtaWat

3000 watt SPL didgital class D amp. I'm not sure what series the 15 is but its one of the older ones..

And i listen to anything. Rap, country, metal, rock, classic etc.

xRiCeBoYx

iTrader: (22)

My JL Audio 13TW5 only requires .8 ft³ of space in a sealed box.. and is 2.5" deep.. But I don't even think that'll fit under the seat.. Then again, it's a 13" sub

edit: lol, 13,000 posts

whitecivic2003

i ask because you have to match up amp output to the ohm load of the speakers to get the most power out of it. also depending on the music may be better to go with one or the other. also 2 12's may need a bigger box than 1 15 but i may be wrong depending on what the speakers themselves are designed to play in. for example the jl 13tw5 only need .80 cubic feet where a 12w3 needs 1.25 cubic feet.

Kennykid2002

iTrader: (1)

Even if the TW5 is a slim mount sub....

If you manage to stick that under your seat, you'd have no room for excursion, causing damage to the woofer itself

TiggerDX

iTrader: (1)

I would have to disagree about mixing and matching subs. There is nothing wrong with having different size subs. Different size subs will not cancel each other out. Having the subs wired with their polarity reversed from one another will cancel each other out.
There are many pro audio speakers on the market that run different size drivers.
And I would be willing to bet you could find cars in the competition circuit that utilize different size subs to enhance different frequencies.
Not to say that throwing different size and brand subs together without some thought will sound good. Impedance, air space, power requirements, sensitivity all come into play.

And why would a different size sub move in and another one out when they are receiving the same signal? (assuming they are both receiving the same signal)
One sub may have a more extended excursion than another and take a bit longer to retract, but unless they are wired in reverse polarity, they will always move in the same direction. With this rational, you wouldn't be able to have 5 3/4 and 6x9s in the same vehicle.

xRiCeBoYx

iTrader: (22)

that's why I said I don't think it'd even fit under the seat..

whitecivic2003

you have a pic of your 13tw5 installed ?

xRiCeBoYx

iTrader: (22)

i have a temp setup.. I'm too lazy and too school-busy to finish it at the moment.. I have a speaker grill over it unlike pictured here.. It's a no-**** JL Audio one, so it fits happy



edit: that box has .807ft³ of internal space. their recommended box size had ~.8ft³ internal airspace without the sub in it, so mine is built to spec. as it sits, the box is 5.5" tall, made of 3/4" MDF

Kennykid2002

iTrader: (1)

I think there is some misguidance here...
What i'm saying, and what I think the OP is saying, is having the 12's and 15's in the same box...
IE.
oOo design most likely

As different woofers move air differently because of the size, the 15 would cause heavy air flow distortion to the 12"s, causing "cancellation" or however you want to call it

Can you put 3 different size subs in different enclosures? Sure thing.
I still wouldnt advise it, if you dont know what the hell you're doing

whitecivic2003

Maybe this will help you understand i was just trying to simplify my previous discription of what happens . not everyone understands frequency response. q factors ect..

The reason is that the frequency response of a 12" sub will be different than a 15" sub, for example. The boxes would play a huge part in this. In order to do what you are talking about and have it work, you would have to use an extensive system of crossovers, in order to separate the frequency ranges going to each sub. You never want 2 different speakers of different type/brand/size playing the same frequencies. they create wave overlap which in turn cancels out some of the sound . and most competition cars are using extensive crossover networks with normally using larger subs for low end bass smaller subs for mid bass and woofers for the high levels but are all playing different frequency ranges.

TiggerDX

iTrader: (1)

Oh, I agree totally. That isn't what I was replying to. Sorry for the misunderstanding. And they can be in the same box if the chambers are sealed from each other.
He could use one box, with 2 chambers and run the 12's in an isobaric configuration.

whitecivic2003

thats cool how do you like the sound? what do you have powering it? i am building the box for mine yea 13tw5 also here is the progress so far

Kennykid2002

iTrader: (1)

Lol, I think we're just confusing the sh*t out of the OP

Bottom line-
If you don't know what you're getting yourself into, I wouldnt suggest it.

However,
If you're adamant on getting all 3 subs in 1 box, we can help you.
You'll just have to know it's a lot of work, and customization

PS. a large bandpass would work if the interior is planned correctly.
Then again, a large bandpass with a 15" and 2 12"s would never fit in a EM2

EDIT: Nvm, I forgot you technically CAN put a large bandpass in, but....removal of rear seats...etc
Steve Meade put 2 18"s in a wall inside his vic =/

xRiCeBoYx

iTrader: (22)

My sub amp is actually a 600W RMS, so I have the gain turned WAAAAAAY the hell down and I don't push it. The way I have it setup tho, it adds a nice bass accent instead of overpowering like I've heard in many other systems. Enough bass to notice I have a nice system, not enough to make you wanna stab your eardrums. I have played with it a bit tho, cautiously turning it up so I don't kill the sub, and it performs nicely.

And the box you're building, I actually had my old sub in that spot. an Alpine type-r 4-ohm 10". Made a fiberglass box just so I was able to get the experience with fiberglass, and so I'd have enough know-how to attempt it again if I so desired.

TiggerDX

iTrader: (1)

He could always take the coil out of the 15" and use it for a passive radiator. More bass and a smaller enclosure. Tuning would be a bitch but that thing would slam. Just mount it rear firing from the 2 12's positioned between them.

OP, just save yourself a lot of headaches and just use the 15 or the 2 12's. Or even 1 12.
Or be totally creative and use all 3 and really rock your world.

xRiCeBoYx

iTrader: (22)

if OP doesn't care about trunk space, just make a badass fiberglass enclosure in the trunk. It's not hard to do. Sure, time consuming and a bit itchy, but not difficult. PLus, you can get creative with that ****, and can keep access to your spare if you do it right

Kennykid2002

iTrader: (1)

Oooh, I like how u threw in that passive radiator suggestion

It would sound badass in a sealed enclosure
But yes, tuning it would definately be a PITA