Box building and choosing subs

I have cruised the forums and did search but with help to me so here I post.
I am construction illiterate and cheap (don’t want to pay a shop 300+ to build).
What I want to do is build a box to fit into my spare tire well, for the subs to sit flat with the rest of the trunk, to not lose any space (need all the trunk space I can get) and to house 2 12’s (which have not bought yet until I figure out how much room I will have in a box).
I have a Saturn SL1 with spare well dimensions of 23½L X 26½W X 7¼H.
My first instinct was fiberglass but after reading it seems complicated (even with walk thoughts). So I figured it would be easier to build with mdf.
Another general question which might help in me choosing a sub is generally how much airspace is needed between the magnet of the sub and the bottom/back of the box?
When I talked to a local shop they suggested Jl 12w1’s, fiberglassed bottom and 2 sheets of ¾ mdf (to support the sub). But that would be me losing 1½ of trunk space.
And if going to have to lose the space and being illiterate wouldn’t it just be easier to drop 2 or even 4 (another shop even told me I could possibly drop 4 12’s) free air subs in?


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Clarion VRX935VD
Clarion DVH940 5.1 Processor
Infinity Kappa 65.7i
Clarion SRK5
Stinger Wiring

Consider this. Given the fact that the box is the most important part of your sub system, would you build your own sub? If you do not have the necessary tools or are not adept at woodwork or fibreglass, have the box built for you as it will guarantee results that you on the other hand cannot. Just my.02

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Top Secret, I can tell you but then my wife will kill me.

box building in saturns is pretty easy as the trunk possesses no major obstacles.


however the trunk spare tire well isnt really optimal for 2 12"s

( i have owned 4 saturns, 1 for SPL, 1 turbo'd,2 for daily)

ideally you may want to check out using the side wheel wells, there is someone who has done it... and it was nice looking.

if you are going to approach the project heres my suggestion.

coat the spare tire well bottom in Fibreglass and resin to make it hard and more resistant to rattling... then raise the trunk floor (read put down a thicker piece of MDF or other building material) and use that to mount the subs... then seal around the lip of the Spare tire well.

Good luck and check cardomain for some installs.

also TurboSaturns.net is a good source of info

I agree with forbidden.  This project you want done is not a walk-through, "just a hammer and a razor knife will do" sort of build.  This is done by a professional if you want everything you asked for here.  Save up your pennies and have it done right.  Those shops you mentioned have already begun earning their pay.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

saturnsubohio:
found someone on cardomain who had done what I am looking but I want mine to drop lower (want to hide them under the carpet, going for a no show install). Looks like it’s just a basic build. I guess my question should have been initially:
Does anyone know of a good pair of shallow mount subs?
I am not opposed to doing 10’s.
Here’s picks off cardomain:




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Clarion VRX935VD
Clarion DVH940 5.1 Processor
Infinity Kappa 65.7i
Clarion SRK5
Stinger Wiring

Hi everybody, what subwoofer would be the best match to sinle Q-logic 12" bandpass enlosure. I was considering Alpine R. And box is not tuned yet.

Thanks a lot for any opinion!

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Igor

You're going about this the wrong way.  Once you choose a sub you like, decide what kind of enclosure to use (based on what's recommended for it, and your liking).  Then either build one (have one built) or buy a prefab to fit the bill, and select an amplifier.  Do some searches in here (upper right of the screen) and read up- you'll find lots of useful links and info.  Q-logic makes several kinds of boxes of all different types/sizes, and yes, they are already "tuned". 

Once you feel you have a grasp of things, you can post back with a question (and create your own thread).  "Best" is about as generic a question as any, and would be like me asking you how "blue is blue?"  It's too tough a question to tackle.  Don't take this like me jumping down your throat, I want to guide you in the right direction so you can ask the proper question to get the info you really need.

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My ex once told me I have a perfect face for radio.

I would like to point something out.

You say you need all the trucnk space you can get. That tells me you're going to be putting things in the trunk.

That would require you putting things on top of the subs. They generally do not appreciate being held down, where they cannot function properly. You may need to consider some sort of protective device for tops of your subs. The half-a aluminum grate style covers from wal-mart are not an acceptable answer either (you know, the one's that cost 5 bucks)

saturn(what ever goes here) has a good idea. the side wells may not be a bad idea.

Remember, you can spend $5,000 on a pair of subs, but they're worthless if you squish them, and put a hole in the cone.

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Greed is for amateurs.

Disorder,chaos,anarchy now THAT is fun!!

Back again still working on my trunk project.

I’m reading that the fiberglass project that I originally was going to try is going to be way expensive.

So I’ve decided to go with just an mdf well.

Now since I’m not pushing a lot of power (460@2ohm) and just looking to get some bass in the back I’ve considered running free-air/ib subs.

With free-air/ib would you still need a divider for 2 subs?

The two subs I’ve been considering are;
Kenwood (KFCW300S) (150rms/600max)
Infinity Kappa’s (102.7w or 122.7w) (350rms/1400max)

As for protection I would just use a sub covers

Wouldn’t I get better sound from the spare well over the sides?


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Clarion VRX935VD
Clarion DVH940 5.1 Processor
Infinity Kappa 65.7i
Clarion SRK5
Stinger Wiring

bass = omnidirectional.. so the "sound" you hear would be equivalent.

it will come down to how you build the box and how you prepare your trunk.. i myself suggest taking off the reflector and tailights and getting some deadening materials in there.

also the exhaust heat shield is a common problem with saturns

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2006 WRX STI
Electrical Engineer
Ohio University Alumni

That would be a no to the free air subs. A free air sub needs as much air space behind it as possible and it needs to be 100% sealed off from the back pressure wave of the sub. What you should be doing is dropping the must have 2 subs idea. Go to one good dvc 4 ohm sub, have the proper slot port enclosure built for it and call it a day. Next thing to consider here is simple. Put your hand over your mouth and talk, that is what you will be doing to your sub when the carpet is over it. Then the carpet is going to flap around like your butt cheeks during a wet fart.....ewwwww. So you have a couple of design flaws to consider here. You can always rebuild the floor of the trunk to come up another 2 inches or so, don't limit out ideas for the box based on leaving the floor where it is.

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Top Secret, I can tell you but then my wife will kill me.

I believe that forbidden really hit it on the head with the wet fart explanation... You really should be looking at the possibilty of building a false floor so that you can have the correct volume and what not. How often do we really need that extra two inches of trunk height anyways...

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If your counting pennies and dimes then maybe you shouldn't be spending every penny and dime you have!!

I have done more false floors than I can count. It is the only way to go if you intend to use your trunk or utility area . Easy to carpet to match, Don't rush on making the top piece, gets some cardboard and make a template for each side. In a trunk I usually use 2 pieces. If your handy enough to do this you can mount your amp under this false floor, I would recomend using a cooling fan and possibley a vent above the amp. The best benefit of a false floor it slow thieves down....

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Ok enough on dreaming of going flat. Reality has hit.

False floor 2 piece?
Would I be assuming that means I would make a box specked to sub then put 2 pieces (shaped to the floor) over the box with the subs open?

Suggested was 1 good 4 ohm dvc, what would be the advantages of dvc vs svc, 2 or 4 ohm, 1 or 2 subs, 10 or 12?

Suggestions on a “good”, “better”, “best” sub? I know that will just open up a ton of suggestions. Currently I have a set of older Kenwood’s. But I know there are better out there.

Image Dynamics for FreeAir

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2006 WRX STI
Electrical Engineer
Ohio University Alumni

The advantages of a dvc over svc sub is the wiring options.  For instance...  A subwoofer that has 2 4 ohm voice coils can be either wired in series for an 8 ohm load, in parallel for a 2 ohm load, or you can even only wire one voice coil for a 4 ohm load.  You must also take into account that the subs power handling will be reduced by about half if you use one voice coil.

There is an advantage of a 2 ohm load over a 4 ohm load, but it all depends on what you want.  An amplifier that can "receive" a 2 ohm load will put out about two times the power in a 2 ohm load when compared to a 4 ohm load.  It usually isn't exactly twice as much; it's usually less.  This can only help you though if your amp is 2 ohm stable.  The problem is...  The lower the ohm load you give your amp, the worse the sound quality is.  Guessing that your a daily listener, this won't really matter.  You probably won't even be able to tell the difference between a 2 ohm's or 4 ohm's sound quality.  If you're in a sound quality competition, then that could be important. 

The difference between a 10 inch and 12 inch sub if usually loudness and bass extension.  A 12 inch sub is generally louder than its 10 inch counterpart.  This is due to the increase in surface area.  Larger subs can also gain a little low end extension.  This doesn't always occur, but a 12 inch sub might be able to play lower than a 10 inch.  Everything I just said though only applies if the 10 inch and 12 inc h subs are the same brand and manufacturer.  Things vary greatly between different lines and brands of subs.

The whole "good," "better," and "best" sub can't really be answered.  There are a lot of things to take into consideration.  You have space requirements, money limitations, and most notibaly, hearing differences.   The best advice I or anyone else on this forum can give you is to go listen to different subs.  Everyone hears sound differently and has a different perception of what is good and what is bad.  I, for instance, find the Infinity Kappa Perfect subs to sound a lot better than many other subs in the same price range and higher.  Someone else might think that the Perfects sound like crap though.  It's all in the ear of the beholder .  So my advice is to go listen to what you can and pick what YOU want.

Well that's the best I can do for now.  If I said anything wrong, misleading, or unclear, then please correct me or ask.

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That's my opinion. Take it, leave it, or correct me.

I would listen to what forbidden said. Drop the 2 sub idea, put your money into a a single, 4 ohm dvc sub with a ~500 watt RMS rating, and have your local shop build you the proper box for it.

I would suggest looking into a single Alpine Type R SWR-1242D - 500 RMS, works well in a 1.7 ft^3 vented box, and imo, sounds very nice.

My amp in Eclipse PA5532. It pushes 200rms/460max@2 ohms. Not a lot of power but it’s clean.

General rule of thumb isn’t it best to match the rms?

Wouldn’t it defeat the purpose of running a high power sub?


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Clarion VRX935VD
Clarion DVH940 5.1 Processor
Infinity Kappa 65.7i
Clarion SRK5
Stinger Wiring

Talked to 2 shops today.
One agrees with the single 12 and another suggests 2 10’s (Kicker cvr10).
1st shop didn't go into any details just suggested.
2nd shop asked and narrowed down a little more also gave me dimensions for building my own box. Based on my choice of music (rock) the 2 10’s would give me the bass to bring out the music.


-------------
Clarion VRX935VD
Clarion DVH940 5.1 Processor
Infinity Kappa 65.7i
Clarion SRK5
Stinger Wiring