sub box

Systems

what would be the best way to go about making a tube style, sealed "box". i would be making two of them, for two gnx104 subs. and maybe do the one end out of plexiglass. any ideas?

neomagus00

i've never heard good things about tubes for subs. if you want the tube look and have a bit of space, you can build a regular rectangular box and form fiberglass/whatever in a tube around that: tube look, box sound and strength. does require a bit more room than just a tube, tho

Systems

well thats my problem, my box now is taking up a lot of space, and with everything i do, i need to be able to get things through from the trunk, to the back seat(i.e. pieces of wood that dont fit in the trunk alone) i figured if i did a cylidrical type of box, it would give me some more space, and maybe more mounting options.

neomagus00

that it may, but (at least for my trunk) right angles fit at least as well. you may wish to just make a simple box, one foot on each side (external), if it'll fit in your trunk. then you can put plexi on one side (not reccomended) or in a window on the side you'll be able to see; screw it in really really well from the inside, and seal it too.

put each box all the way against the back seat and along the side of the trunk. this way, you have the whole center and probably some of the rear free. note that the 12" cube will be cutting it a little close on driver clearance, so go with a 13"x13"x8-3/4" box if possible.

there are designs that are easier to carpet and look a little better to boot, if you want, but they're slightly more difficult to build (read design for me).

the primary problem with tubes has to do with standing waves - the curved interior reflects the back waves of the driver around the box. i think. in any case, its bad.

Systems

well is there a way to maybe cutdown on the wave reflections? i know polyfill slows them down, but maybe another material?

neomagus00

if you're dead-set on the tube form, lining the inside with that egg-crate-looking foam may (may) help. you know, the stuff that looks like a 3-d sine wave? this may help diffuse the internal sound waves.

generally, anything that can be used to build a tube will have to be hard, and thus reflective. i'm getting the foam idea from a product dynamat sells. it is placed behind a speaker to diffuse the backwave. this is good. i'd say use a bunch of these to line the interior of the tube, but that would become prohibitively expensive quite rapidly.

oh, and your original question was how to do it. i have no idea how plexi- or fiber-glass is formed, but rolling it around something already round (such as a scuba air tank) may make things easier. honestly, you should probably ignore this paragraph.

Systems

well this is kinda where i got the idea from
http://www.crutchfield.com/roadtest/turner_crx.html
but thats brushed aluminum. i would kinda want it like that, but with fiberglass rather then the alum.

Systems

or there is one other idea ive thought of, if possible. it wouldnt be even close to fun to do, but maybe taking mdf, and making a shitload of rings, kinda like a mounting ring, and stack them untill its big enough. would that work or am i crazy? then maybe wrap it in figerglass for appearance.

neomagus00

while concievable, you'd waste an awful lot of mdf; sealing it would be horrendously difficult in any case. and isn't the point of fiberglas to be able to see the inside, or am i totally backwards on this one?

i see what you're going for, but i think its more for looks (like the rest of the car) than for sound.

you could go get a tree and drill out the middle...

Systems

well no, figerglass isnt see through, maybe the resin is, but the resin has to coat something, like fleece, or even fiberglass matting. so either way, you wouldnt see through it.

neomagus00

Fair enough - like i said, i dont exactly know about plexi . the ring thing might work, tho - if you make a few rings, you can use them for internal bracing in the fiberglas tube. it may be better to use a solid ring with a big hole drilled in it off-center than an o-ring kinda thing. (hey, i rhymed!) anyway, the offset hole will reduce the standing wave problem. throw a few of those in, and bracing and standing wave problems are solved in one fell swoop. whaddya think?

Systems

so take a few of those and kinda place them randomly in there? i saw you guys say something like that in a box, i just dont remember.

sntnsupermen131

im not sure what exactly you are talking about in the past 2 posts, but the making a bunch of rings and gluing them together would not work
you would probably have about 10000 air leaks
fiberglass is not see through
plexiglass is see through
how would a cylinder save space?
i would think a sqaure box would be the smallest...its maybe an inch taller...but a cylinder would be very long
and i have no idea what a cylinder box would do as far as resonance goes...
-Cody

Systems

my trunk is kinda shaped weird, so with a cylinder, id have more options as to where and how i could put it. i also think it would be more appealing visually.

Airplay355

lots of HT woofers are tubes, or cylinders, why wouldnt it work in a car?

neomagus00

hmm... why does adire reccommend only their 15" brahma for home audio use? perhaps irrelevant, perhaps not...

exalted512

no idea...
you can ask sandt38 on www.caraudioforum.com
he'll know
-Cody

LittleCar_w/12s

Ok here is a design I came up with for you.
It has aesthetics, as well as functionality and saves space.
GIVEN you know how to bend plexiglas, this will look nice for you.

The image included will help you understand better.
First I show how a 13.5" round has 143 Square Inches of surface area, causing it to be made 11" deep. then You see a square enclosure has 182" S.A. and is only 8" deep.

Your solution then is to build a partially round can/box that has a s/a of 172" sq. and is only 9" deep.

For aesthetics, the round side can be made out of plexiglass if you choose. I would use a thick aluminum for the other two sides aif using plexiglas on the round, then use dynamat on the flat sides, then cover that with a sheet of craft foam (about 1.8" thick) which will allow you to choose the color of your box's interior as well as hide the construction seams.

This will be as small as you can get a 12" sub into your trunk and still conserve the area of a right angle type box. Not only that, but it will be easier to mount because of the flat side.

Any ?'s just ask.

--Jerry

LittleCar_w/12s

Hmm i made those specs for a 12" sub... you could re-do them for a 10" fi you want.
Sorry...
--Jerry

dtownshoots

for a tube... i have no idea how that would work on making it yourself. i only know how to do wedges and boxes and those prove hard for me. If i were to do a tube though, i would make the tube and somehow mount it on something in the car, but dont take it from me, i just have a single box