so i think i'll soon be building a new box, and switching subs. my plan is to have a 12w3 in a ported box built to spec (volume-wise. as far as dimensions, the box will be custom and incorporate flushmounted amps on the top.) from the jl site. i'll have the sub downfiring, but i'm not sure where to have the vent exit. i guess my question is, is placement of the vent/port important to the tuning? so if i have my sub downfiring, should the vent be on the bottom as well? would it make a difference if it exited on the side? are the ONLY things that affect the port/vent tuning its size/volume, and not where it exits? how about the shape of the box? the one i'm planning on building, will be wider and shorter versus the box illustrated on the jl site. does that make a difference in ported boxes? or is it again only volume that needs to be correct?

my plan was to have it the vent hole on the side.

oh and if anyone has any ideas for creative (and clean) ways to light a flushmount setup, let me know :o)

 

For, the box, StriderO0O (sp?) recommends that the sub face forward and the port be on top. I imagine it would be alright if the sub were to be downfiring. As long as there is nothing in front of the port within a couple of inches, it sould be mounted on the side. Just make sure that the volume and port length/area are correct as per JL's recommendations and you'll be good.

 

you've got the zero's and o's reversed! lol.


but anyway, ive seen many records set with that box setup (subs faced forward, ported out the top). for that reason, i reccommend doing so if you're looking for a good stance.

as for placement of the port, the design of the box plays a part, somewhat. easiest thing to remember (common sense), DO NOT place the port directly behind the sub, firing outward directly behind the sub, lol. a simple rule of thumb would be; you should not be able to see the sub when you look into the port.

like i said before, box design is important, as everyone knows. the more irregular angles in the box, the better. the absolute worst size box is a perfect cube. when you build the box, try not to have any parrallel walls, if possible. (you're bound to have some, just dont have every wall parallel with another somewhere else). bracing within the box can help break up some of those walls a little. then of course there's accoustical matting (recently mentioned in a few other Audio/Video threads i think). many things can be done within the box, to help it out, acoustically. that's pretty much the tip of the iceburg for things to remember when you start to design and build your box.

placement of port- you'll get a few different points of view on this. ive read a few books that recommend not having the port any close than 3 inches from any of the walls (and of course, dont have them extend from one face on one side of the box, to an inch or so away from the rear face at the other side). with that said, you'll find many, many boxes with vents built into the box, basically as the box's exterior wall. so for placement (within the box), i can only say, just build the vent or port to specs, and try not to go with the cheapest and fastest way to build it, if possible. take your time with the port, it'll be the most crucial part of the box when it comes time to build. a bad port can cause the entire project to turn to ****.

 

thanks sean... i'll run the box plans by you when i'm finished to get your opinion ;o)

 

the jl plans call for a vent that shares one of its sides with the exterior wall of the box. the vent is also approx. 21" long, and goes along the side of the box and wraps around to the back. my design will still incorporate the 21" long vent, sharing a side with an exterior wall of the box, however my box will be much wider, so the vent wont bend, but instead will run along the top inside of the box out the side, with the sub downfiring...

 

ok heres a very basic sketch of what i'm thinking of. the width will take up roughly behind my seat and the middle (about 2/3 the width of the space in back) the front will be angled (i didnt draw that in the silly drawing)

 

i've seen jl's box recommendations, so i know what you're talking about. your box looks like itll be fine. like i said.. some say one thing, some say another. what you've got there looks like it should be just fine.

 

Chances are once you build one box, you'll probably build another one again. So let the fun begin!

 

hehe yep already there.... here's the current box i built last summer that i'll be replacing:





looks better in the truck after i changed the int. to black...

 

^ nice box man. I like the glass look. You should turn the amp upside down on the next build, I love to look at the circuitry in an amp.

(Im guessing yours has a clear bottom?)

 

Nice setup...