i know ive posted a couple times before about ideas for a speaker box, but they havent been at all what i thought they would be. i have 2 kenood 10s w/ 500watts and a kenwood 600 watt amp. i want the box to sit on the hump behind the back seat. so it will measure 39x7.5x15 INNER diameter and ill be using 3/4 particle board. that comes out to be roughly 2.5 cubic inches. a couple people ive talked with who build systems say this is a good size. my previous box was 39x7.5x11.75 which is, i believe just under 2 cubic feet.

ive also been told that im better off wiring the subs this way: run one positive from one sub to the amp and one negative from the other sub to the amp. then connect the remaining pos and neg together. will i get more power and better sound by doing this? sorry if any of this isnt clear enough. ask if you need more clarifiaction

thanks

 

The below link will explain the wiring. Can't really give you a straight answer on wiring without knowing if the subs are SVC or DVC and the ohm of the models. Also the output of the amps all differ so clearification is need'd on the model number for further help.

http://jlaudio.com/tutorials/wiring/index.html

Normally you try to wire the subs for the max output from the amp at a stable ohm. Wiring isn't to be taken lightly because one you can miss wire and the subs don't get all the power they should or two if you mess up the wiring it can actually damage the amp.

As for the box size that depends on sub requirements. That changes from sub to sub. 0.5 cubic difference isn't that much. So if you were happy with the old box you should be just as happy with this one.

Make sure to use tee nuts for the sub mounting holes, else removal of the screws over time will tear out the wood and eventually won't tighten down the subs anymore. By using tee nuts you get metal threads to pull the screws. They can be found at about any hardware store... usually seen in building cabinets or something along that line.

 

U mean on the "shelf" behind the rear seat? That's where my box is... 1 problem I had w/ that location is that the box slides backward when u accelerate hard. There's a hole in carpet for the flat-tire tie down, so I stuck a piece of particle board in that hole. I pushed it far enough forward to wedge the box against the back of the seats and it doesn't move.

The other problem w/ this location is cancellation. Part of the bass wave goes to the front of the car, but part of it goes to the well and reflects forward and interacts w/ the front wave. They'll be in phase around 40-45Hz and it will pound, but they'll be out of phase around 70-80Hz and u'll barely be able to tell u have subs. If I ever get around to it, I plan on building a downfiring box so all the bass goes to the well and then forward.

Do u have a 2ch amp? If so, then u should wire it as u described off the bridged channel. Unfortunately, u'll be running into 8ohms and u'll only get about 1/2 the power then amp is capable of -- u could wire for a 2ohm load, but the amp won't handle that on the bridged channel. If it's a monoblock amp, wire the subs in parallel for a 2ohm load.

 

what are the specs on your box as far as dimensions? and what did you use to build it?

 

I don't remember the dimensions offhand... I built it probably 6-7 yrs ago. The dimensions u listed are probably close though. It's about 1cu ft per sub and I used 3/4" particle board. It's hard to tell from the pic, but it's also angled a little bit -- it roughly matches the angle of the hatch glass. Here's a pic of the back of the grill... I used window screen so the carpet wouldn't sag.

 

sub boxes on the rear shelf can't compare to the output quality of a well box... IMO

 

Have u ever heard a downfiring box w/ walls on 3 sides so all the bass goes towards the well? I haven't, but in theory it should solve most of the cancellation issues of putting a box on the shelf. The problem w/ a well box is that u'r pretty much screwed if u ever get a flat tire -- I don't like the idea of putting a greasy, dirty tire in my back seat

 

I'm pretty sure there would be plenty of room in the back for the flat tire in the spare tire well. Even if the flat doesn't fit there, I would just move my sub box to the back seat and put the flat in the well. OR, you could just carry around some plastic bags to cover your backseat if this happens. I keep some for when it rains hard and my t-tops leak.
I wouldn't let this stop you from building a box in the well.

 

I just keep a trash bag in the spare tire compartment.

 

so if i build one to fit in the well, do i leave it an open? basically build a shelf back there or do i have to seal it all up?

 

What do you mean by leave it open?

 

For quality sound, you do NOT want open-air subs. Seal it up. Trust me, I had a pair of Rockford 12"s and a pair of MTX 12"s of about the same year, same power rating. The RF's were on a plate, the MTXs were boxed. The MTXs sounded a million times better.

 

so i guess im not going w/ the box on the "shelf". i want it to sound better than what i had, cause i know it can sound a lot better. the subs were the circuit city "buy one, get one free" $100 deal. theyre 500 watt max, 4 ohm, w/ a 1000g magnet. theyre KFC-W2503. its all that the sub says. i dont really know a whole lot about building systems. the amp is KAC-728s 600 watt max power. based on that, what do you all suggest for box size, location, wiring, etc. i dont wanna have to do this for a 3rd time around. i want this to be the last time and be as good as i can get.

 

You definitely don't want a free-air system. They don't sound good.
First off, if you can return the equipment to Circuit city, I would consider that. There are better subs than Kenwood that won't take up your whole trunk.
Before you buy anything, you should always do your homework. Read all you can about amps and subwoofers and how to install them.
You are going to want a sealed enclosure for the sub if you want to build this for yourself. It's not a good idea to build a ported or bandpass box if it's your first one. You're going to need to understand Thiele-Small parameters and what they do. I will say it again, you need to do your homework before you build a box. Learn the physics, do the math, build the right box - it's the only way to do it right.
Or have someone knowledgeable build the box for you. If you just build a box of random size, there's no telling what it will sound like. Unfortunately, there aren't many pre-made boxes that fit in our cars, however, there are some people on this forum that do these things. REZN8R is one of them, and from what I've heard from other forum members, he does a heck of a job.

 

the subs and amp are about 4 yrs old. i got them w/ a car when i bought it from my brother, so no chance of returning them. i really dont want to buy new ones either, i have lots of other things to put my money towards right now like engine, wedding...... which comes first, lol. so what can i do w/ what i have?

 

Well I still don't like the idea of a well box... yeah u can put plastic in the back seat, but the tire is gonna move around and probably still rub on the interior (not to mention it could disturb u while u'r driving). And trust me, I speak from experience w/ another car -- u don't wanna be fighting to move a sub box around when u'r stuck on the freeway w/ a flat tire!

On the other hand, the possibility of getting a flat tire is pretty low, so maybe it's not much of worry. But I would at least keep those potential problems in mind and be prepared for them.

Anyway, getting back to your question... I would try searching online for the model # of the sub. Try to find some specs and recommended airspace. U should be able to design a box w/ that airspace -- and a box that is correctly matched to the sub, built well, and placed in a good spot can make even an old, cheap sub sound pretty good.

 

If you're worried about fighting with a sub box to change a tire, you have no business putting a sub in a third gen in the first place (especially not TWO of them).
Where else would you put it? On the hump? There's hardly any room up there unless you build it so you can't see out your rearview (not good), and is also a permanent advertisement for thieves (not good). In the back seat?
With that said, the box I built does fit in the middle of the well, rises to just about the level of the privacy cover, leaves room to access both the lock box and the spare tire area (and room for a flat tire with that panel removed), and even leaves room for a carry-on bag. However, I can't store my t-tops in the back, and it would sound better deeper in the well.

 

put it in the well, or not it all

in my opinion...

in the EXTREMELY RARE chance of you getting a flat... keep.. I don't know... two, three, hell TEN trashbags in the spare tire compartment... how about a tarp? Whatever you want...

that tire's only going to be in your back seat for, what, 10 minutes?

I usually just hold mine in my lap.

 

U can see a pic of my box earlier in the post... it actually sits just below the top of the back seats, so it doesn't block the rear view at all. I have 2 10s in there and I have a similar box for 2 12s -- and I don't have to fight w/ anything to get a flat in there. As for the T-tops, I slide them right down into the well. Yes, the box is noticeable there, but w/ the grill, no one can see what's in it. And w/ the matching carpet, it's not really gonna catch your eye. A thief can see it if he's looking for it, but then again, he can see a well box too.

So w/ this box design, it maintains virtually all of the access and functionality of the well area. The only thing I don't like about it is the freq response, which I think I can fix w/ a downfiring box.

 

They don't see anything in my car b/c of the cover! Now that I've put in the soundproofing, the only way they can tell I have anything is by the cover bouncing up and down when the bass hits

 

the one thing I actually like about our car's bass response is if you open the hatch, it bounces right off the glass... so you can be the life of the party...

 

This happens to you often?

 

actually, I've only used it once the entire time I've owned my car... and I COULD have just filled it with air, as I was putting on the spare AT a gas station...

I definitely wouldn't get RID of the spare... but I won't make any special accomodations for it either.

 

i never ahd a spare... when my tire went flat i had to call my dad who lives 30 mins away to steal the front tire offa my bros monte so i could get to school the next morn...lol i dont care about anything except changin lightbulbs

 

what if you were 500 miles away from home after 5pm?

 

AAA

 

cry and start walking... duh... gosh what do you think

 

Donuts are only good for about 50 miles anyway. You're probably better off calling the tow truck and paying their bill, rather than replacing the donut after you use it. I'm only going through that fiasco if it's my last shot.
Vote for Pedro!

 

lol i never saw the movie but i heard enuff of it to want to see it

 

Such a good movie!

 

on topic:
donuts are good for much more than 50 miles... but not much more than 50 miles per hour
I guess our OLD donuts may be no good anymore... but hell... you could get the donut rim, and put on a honda civic tire or something...

off topic:
that movie was f'd up... it's really only funny in the sense that it's really damn dumb...

plus I have a friend that reminds me of napoleon.

 

LMAO