Hey guys!

I have a huge favor to ask of anyone who might be willing to take on the task (if it's even that big). I would like a sub box that fits my trunk perfectly, but I have no idea how to design it so that it has the right air space. I have two 12" Kenwood subs in a sealed box, but I'd like more sound (who wouldn't).

The box the subs came in gives dimensions for a recommended box size, but I only have 35" of width to work with so the box can be between my wheels. Mitch Trewyn suggested I somehow put the port in the back somehow. I'm not sure how that would work, but that's the whole reason for this post.

The recommended air space for each sub is 2.0 cu.ft. The outside dimensions for one box is 23-1/4" W, 12-1/4" H, and 14" D. So is there anyway to move the port around, or make it deeper and less wide? I have no idea.

Thanks to anyone who even attempts to figure this out. I have NO idea even where to start.

Thanks!
Tyler

 

what subs are they? and ill give you a cut sheet. if your gonna rock the the port in the back. your gonna want to fold the rear seats down. other wise personally id go port facing the rear of the car with the subs. but its up to you. your gonna get alot of rattling on the out side of the car with the sub and port facing the back of the car just an FYI

 

the subs are kenwood kfc-w3013ps. 12" 400w rms, 4-ohm. I wired them down to 2-ohm so I could use a monoblock amp (hifonics hfi1000.1d). Not sure if any of these specs matter, but that's how it ssetup. I always put down my back seat just because I've found that it hits harder that way. I would reall appreciate it if you could with a rear ported box!

Thanks@1
Tyler

 

tyler, didn't you say that you didn't think a port would fit up front with the subs? i forget how the conversation went lol

 

Yeah I'm not sure a port will fit in the front (where the subs are), unless you make the box kindof T shaped, if that's possible. I took some measurements for this T shape, but I have no idea how the ports would be incorporated. I made a drawing and it's attached below.

These are the BIGGEST dimensions the box could have. And I forgot to put the max height, but it would be 17".

 

you got a PM sir..

 

Just a FYI, having the port on the back of the box and the subs on the opposite surface of the port will induce a crap load of cancellation due to the front and rear sound waves being out of phase with each other.

Your subs are spec'd to work well in a port box between 2 and 2.5cu.ft. per sub, based on the amp you have (which isn't likely to actually do rated power) and the fact that even if that amp can do 700rms @ 2ohms you'd still be underpowering them by 100rms, I'd suggest going with a box that's closer to the larger end of the spectrum. At least split the difference and go 2.25cu.ft. per sub. If you had like a 500 watt amp, then I'd say go with the largest ported box, but you're not that far off.

 

fiberglass it for a perfect fit. I covered the corner of my trunk in tape, then aluminum foil, then painted on a layer of fiberglass resin, then about 4 layers of fiberglass matte. It's custom fit to the corner of my trunk (no wasted corner space) and i built it out enough to get the right airspace. Granted that's all for only one sub, but when you're going for more quality than volume, it works.

 

I replied to your pm boxman.

Milhouse: I'm not sure how all those waves and things work. Right now I'm running each sub at 2-ohms and 350w rms.

Jester: I would love to get into fiberglass, but that'll probably have to wait until spring time.

Thanks guys!

 

That's why i'm helping you out

Who told you to put the port on the back side of the box with the subs on the front side anyway? I'd make sure not to take advice from that person when it comes to audio stuff

You will easily have room for a port on the front side of the box with the subs, don't even worry about that. So you're gonna be underpowering the subs by 100rms, which is why I say go with a larger box. A good general rule of thumb is this: underpowering = larger box, rms = medium box and overpowering = small box. Kenwood says that sub can be put in a ported box anywhere from 1.5 - 2.5cu.ft, with 2.0 being recommened....I still say you should do 2.25per cause you need a box that's more efficient since the subs will be getting less than rated rms power. So you're gonna need a box that's roughly 4.5cu.ft. after port and sub displacement, and tuned low.

So what I came up with is a box the following specs:

16.5" tall x 35" wide x 21"deep, the port will be 3.5" wide x 26" long and your tuning will be about 30Hz. Internal volume of the box will be 4.49cu.ft. after displacement and it will slide right into your trunk with no problem. Let me know if you like the sound of that and I can get the design over to you.