PDA

View Full Version : Enclosure Design Fundamental Q:s



TimberJon
04-21-2004, 04:08 PM
I dont know anything about subwoofers.
I can only guess that the bigger the volume, larger the drivers, and more power they can handle (RMS) the larger the ports, or more ports will be needed.
Id like a box that can utilize my two JL 12W7-3s, and through slot-style ports, fire both into the trunk, and into my cabin from between the rear seats. Attatched is some rough sketches of my ideas.

What i dont know, is the math required, (the formulas wont even help me) and the fundamentals. Ive seen 4 round ports, but slot ports arent the same.
To get an idea of where im going, i need to know if: when you add more ports, does the volume in the box have to increase or decrease? does it matter how far the bass has to travel out of the slot-style port? Im curious, because of my intended design. If it can work, Do i cut the volume? or add some.

If its just stupid, then can i just stick the usual Two ports and fire them into the cabin? The box design would be odd if thats the case. I'll have to think of how ill do that. im thinking (top view again, drivers at the bottom) start the channel at the front of the box, run along the sides to the back, angle 90 degrees to the center of the back panel, and exit, dual slot-style.

Possible?

TimberJon
04-22-2004, 01:15 PM
taps foot...

paikiah
04-22-2004, 10:09 PM
larger the volume, the less power it needs, as the subs will be more efficient. :)

as for your designs, I really haven't thought about having dual pot exits like your first design. your second design resembles a bandpass, and it usually doesn't sound good.

if you add more ports, the port legths will have to increase dramatically.

search for the net for winISD pro and play around witht the program a bit to know what is possible and what is not.

TimberJon
04-23-2004, 12:35 PM
Thank you..

you mentioned that you really havnt thought about dual port designs. If i dado and rabbitbit the necessary places for structural support, liquid nail, drywall screw every 4 inches, and vulkem (sealant used in petroleum industry) the joints, do you think it would work ok? i can always start over. But id like to know if there are any negative effects of having the port structure like that. should i shorten it? you said lengthen. do you mean make the channels run longer?

TimberJon
04-23-2004, 12:35 PM
yes 2nd design was a quickthought, scratch second idea.

TimberJon
04-23-2004, 12:52 PM
after staring at the 1st CAD drawing for a min or two, i see it this way.

If the W7s are mounted facing the rear of the trunk, then its a dual ported enclosure. Its firing open air into the trunk, through the ports into the trunk, and through the ports, into the cabin. Since its not sealed by the subwoofer itself, the cabin and trunk are almost sharing the air space. Im wondering about bass boosting properties, or cancellation issues. I look at it as the ripples of bass the subwoofer it sending out, and how the waves are coming out of the port in the trunk. do the waves hit each other and mess up? or does it all sound the same.

The front of the sub is pushing say 50% of the air. but the rear of the sub (inside) is pushing air out the rear - 25% - and back into the trunk - 25%.

SO, i see two points pushing air into the trunk while there is only one point pushing air into the cabin. it may not be air.. but its how i visualize it.

Q: will the bass bounce off the trunk, and get ****** into the cabin? like the pressure of 2 against 1? will it equal out? or would it be better to fire the 2 points into the cabin, where the greater volume is?

As you can see i really want to know what will work, but id rather experiment with the ideas until i get some facts down, than experimenting with the time and materials.
Ive got to be raising valid questions here..

Would it hurt to narrow the channel width going to the trunk by half, and keep the channel to the cabin twice as wide as the trunk channels??
That might help.

Does someone have some prefab pieces they can try this concept out on?

paikiah
04-23-2004, 01:07 PM
yes 2nd design was a quickthought, scratch second idea.
Well, looking at it again, it's really a 2 ports per chamber design. It could work, but unnecessary.. i'd also be concerned about cancellation...

Again, to get dual ports, the length will dramatically increase.

TimberJon
04-23-2004, 01:30 PM
Ive seen some dual 12" boxes that house 2 ports per chamber. but only round ports. plastic.. and spun aluminum. Never seen it done with slot styles either. Im gunna get WinISD pro, i had it once, and lost it somewhere. i might have it on backup. But i dont remember seeing this kind of factoring in there. If it says yea i can use 1 slot port per chamber, and the length needed is this much, can i cut that in half and add the 2nd port for that chamber?

anywho. If the channels need to be longer, can only one be longer?
Is the second drawing feasable? looks awkward..

paikiah
04-23-2004, 11:06 PM
I always thought if you run multiple ports, it should be of the same length, else it would be an awkward push pull port.

There are no problems if you were to extend the ports outside of the enclosure...better for increasing box volume. :)

And if you try winISD, it'll show you that if you want one port, it'll show you "Z" number of inches. If you select 2 ports, then winISD will give you "Z" x 2. I would still keep to using a single port per chamber, or beter yet, use a common chamber and a single large port that'll vent into your cabin.

TimberJon
04-26-2004, 02:53 PM
ok i redid the strange box. where originally i had two channels ending up in 4 ports, i instead... created two channels exterior to the original box, thus keeping the target volume, but increasing the box's overall length and width.
look better?

As it is, i reinforced the wall between the chambers to match the thickness of the front walls. Something about it being thin gave me the ticks and i started to twitch. anyways, IDEA! ding. With this box setup, matching Factory specs for the subs.. Could i... share the chambers, make them common, with say.. two 4" Holes stacked?

Also, when i calculate the internal volume, do i add the channels volume? or do i stop where the channel starts. or do i add half the channels volume? Say each chamber had to be 2 cubes, does the channel count? or do i double the volume of the channel and subtract it from the 2 cubes? *spins around and falls, dizzy*

paikiah
04-26-2004, 09:50 PM
Ok, the second attachment looks more familiar to me.:) I'd prolly go with that, so much easier to calculate.

Some people choose to go with that divider in the middle,but I'd prefer a single large box instead, to increase volume (generally, larger volume = louder).

Yes, you need to take the channel volume as part of the port. So therefore, when you calculate the net volume of the box, it's

net volume = gross volume - (sub displacement + port displacement + any other extra wood)

TimberJon
04-27-2004, 01:11 PM
GOODY GOODY!!

So, better box design.. should i use any sound dampening materials to line the walls of the box or chambers? in the walls maybe? i can use compression fittings to allow the thinner walls to retain their rigidity.

I put a hole in the center wall of the box. Id like to keep that piece there for structural support. Rounded edges and a simple router job would finish that piece up. Look good?

paikiah
04-27-2004, 01:15 PM
GOODY GOODY!!

So, better box design.. should i use any sound dampening materials to line the walls of the box or chambers? in the walls maybe? i can use compression fittings to allow the thinner walls to retain their rigidity.

I put a hole in the center wall of the box. Id like to keep that piece there for structural support. Rounded edges and a simple router job would finish that piece up. Look good?
Yes, that's what I refer to as a brace, for structural rigidity. Try to smoothen out the edges, especially on the ports (using the 45 degree angle blocks like on your previous drawings.)

paikiah
04-27-2004, 01:17 PM
oh, and I wouldn't waste tiem with the damping material in or around the box.

what you could do is to use resin and make sure all panels get a single coat. ;)

TimberJon
04-27-2004, 01:55 PM
will do. braces will take time to cut on the back panels. but at least i have an idea. Should i use an inch MDF for the front and center walls, and 3/4 for the rest? or 1/2?
resin is a wilco. no prob there. and a good idea..

paikiah
04-27-2004, 01:58 PM
will do. braces will take time to cut on the back panels. but at least i have an idea. Should i use an inch MDF for the front and center walls, and 3/4 for the rest? of 1/2?
resin is a wilco. no prob there. and a good idea..
If they are to get over 1000w RMS of power, then I would recommend a 1" MDF. less flex = more SPL.

TimberJon
04-27-2004, 02:36 PM
I use the resin used in the petroleum industry. Get it from Smith Fibercast.
how thick should i apply the resin to the interior of the walls. Just a 16th of an inch will affect the volume. Shall i make it an eighth of an inch thick? does it have to be a thin wall?

paikiah
04-27-2004, 02:40 PM
I use the resin used in the petroleum industry. Get it from Smith Fibercast.
how thick should i apply the resin to the interior of the walls. Just a 16th of an inch will affect the volume. Shall i make it an eighth of an inch thick? does it have to be a thin wall?
A single coating is all you need. :)

TimberJon
04-27-2004, 02:56 PM
I dont think they will hit 1000rms. BUT, they're close, i think....
Id rather just make it an inch thick just because, rather than having it thinner than that, on the front baffle only. Now i dunno if its true, but i read that JL subs ship with a factory baffle installed, or in the box, that true? if so, should i find out how thick the Baffle that they recommend is? if its 3/4" then i might consider it. 1/2 is too thin in my eyes. Id rather have a solid tank in my trunk, than a fischer price toychest. Ive seen some very nice Thunderbirds and etc... that have a cheap box in the trunk that just flaps all over... everythings loose and what not. ew.

Question on the underside of the box.. between the trunk floor and the MDF.
Does the bass engine sound better ON the chassis? or on another piece of MDF (thats how ive usually seen trunk layouts...)

For my PC's sound system i have my 8" sub firing downward, ported. But the sub is sitting on the bottom shelf of my computer table, which is more like a workdesk. I noticed, that in its little cubbylike shelf, it hits like 5 times harder than if it was just sitting on the rug. I even tried the kitchen tile, and its still better on the MDF. But its only 3/4" which is nice...
But its on wheels, which dig into the rug a bit. all in all, the 3/4" panel sits about 1.5" above the rug. Ive been thinking something about this.. and im wondering if i should elevate the enclosure from the floor that will be attatched to the very bottom of my trunk. Does that sound right?

I believe my box would put out more bass if it worked by itself.
If it was attatched almost directly to the chassis, then it would vibrate the entire trunk probably... but not put out that much bass. This is just my opinion.. based on toying with getting the best bass out of my PC's S.system.

I can provide a sketch of my idea of elevating my box. It wouldnt be more than an inch, 2 inches maybe.

On another note, i thank you for the time to help me clarify ideas from realities and hammer out the little details. I really am very grateful.

TimberJon
04-27-2004, 05:57 PM
floor concept. might use a wall to close off the under-enclosure space from the space where the electronics will be. Might leave it open. Might port the floor on either side so there isnt any stress or pressure under there. wouldnt want it to be completely sealed. Might use some short plastic grills with a short port under it on each side of the enclosure. going to have to stiffen the suspension in the rear too...

paikiah
04-28-2004, 02:16 AM
Ok, I think I see wha tyou're trying to say. Yes, if the box was in direct contact with the chassis, I'm sure it'll vibrate to no end. This is why I, like you, have false floors, with heaps of damping mats and carpeting to minimise vibration.


Yes, the recommended thickness of wood is usually 3/4", 1/2 is too thin, and 1" would be safest. THe baffle that you talk about, I think I have seen some people use that, although more professional people will do away with it and build a new one. I think the baffle is acutally just to prevent the sub from damage, dunno if it's recommended that you actually incorporate it into the box.

TimberJon
04-28-2004, 02:48 PM
THe baffle that you talk about, I think I have seen some people use that, although more professional people will do away with it and build a new one. I think the baffle is acutally just to prevent the sub from damage, dunno if it's recommended that you actually incorporate it into the box.

Yea i heard it was mainly for packaging. probably a nice built-in way to keep the sub from moving around in the box. What i was saying was, if JL recommends a baffle of THAT thickness, then i would design my front wall that thickness. If its just for packaging, i'd go with the 1" front baffle. my theory is that the company would not want to use 1" material for packaging. its not cost efficient. I dont know whats used.. ive never seen the sub mounted to a baffle right out of the box. im curious though..

I had no intentions of joining the supplied baffle (if any) to my box.

TimberJon
04-28-2004, 03:00 PM
going back to my last top view drawing, the one you said looks more familiar.
how would i goop up that box?

I'll cut, dado, and dry-fit all the pieces.
I can screw, glue, seal, and resin everything on the bottom, but i'll have a hell of a time doing the top wall when i fit it on top of the box. I wont be able to get into the channels to complete the braces there. i can pre-mount the braces on the top piece, but then i cant get my hand in there to goop the seams and resin it. suggestions?

Also, how much damping material should i use in the trunk, on the walls for certain. Up against the back seats, sure. But under the false floor? should i sandwhich a half inch or so between the bottom of the false floor and the metal floor? You said you used lots of carpet to help dampen the vibration. Floor and bottom of the box?
My theory was that if i elevate it from the floor, on pieces that move freely but not too much, then the bulk of the vibrating would happen with the box, and not carry down to the false floor. If its bolted right to the false floor.. the floor is also bolted to the chassis, and it just carries over.

The Box would be kind of like an earthquake test. I may not even have to put that much dynamat or whatever on the trunk floor or walls if this idea works.
I just, again, have to know if its credible. If it has a chance of working.

BTW ya seen Alpines crazy mini cooper?

paikiah
04-28-2004, 10:00 PM
Apply resin before attaching last piece then. Simple;) Any extra work can also be done via the sub cutouts.

The false floor nad the isolating thing, I think you're taking it too far. If you wanted to "float" the box", then you could simply use large blocks of erasers between bolts to further assist in damping.

I don't know how you're going to deal with floating it. When I said carpeting, I meant all surfaces that would touch eath other. None of my wood has direct contact with each other (save the MDF panels on the box), which has about three layers of damplifier and covered with carpeting to hide the goo.

As for assembling the box, seeing that your login name is timber jon, I tkae it for granted that you would've had experience with wood. THe only thing you forgot to mention is pre-drilling. As you might know, MDF is very different from timber. without pre-drilled holes, MDF will split and weaken.

TimberJon
04-29-2004, 01:30 PM
The false floor nad the isolating thing, I think you're taking it too far. If you wanted to "float" the box", then you could simply use large blocks of erasers between bolts to further assist in damping.

Large blocks of erasers between bolts? i thought about something like that..
But wouldnt i have to mount the bolts through the bottom of the box? i couldnt just do it on the outside edges, thered be no support in the middle.


I don't know how you're going to deal with floating it. When I said carpeting, I meant all surfaces that would touch eath other. None of my wood has direct contact with each other (save the MDF panels on the box), which has about three layers of damplifier and covered with carpeting to hide the goo.

At work we have 2 and 3" (height) crossbraces, much like i drew in my floor drawing. Theyre about an inch wide, and almost solid rubber. I think they might be plastic with the rubber formed around it. I dunno. Their sturdy, but flexible.
I thought id attatch a length across the front end underside, and rear. Then lay 3 or 5 pieces inbetween, perpendicular to the lengths. Its the same thing as eraser blocks, but without the bolts.


As for assembling the box, seeing that your login name is timber jon, I tkae it for granted that you would've had experience with wood. THe only thing you forgot to mention is pre-drilling. As you might know, MDF is very different from timber. without pre-drilled holes, MDF will split and weaken.

Lmao. strangely enough, i do have woodworking experience. not as a career or trade, but Advanced woods classes from JR high through HS, so 6+ years. So i know the fundamentals. Including the pre-drilling. i remember typing it, but i think i deleted it as i was trying to reword something.

My name though, is a Zonename from Zone.com, i play a PC game there. the Timber is the first part of the name of a walking robot called the TimberWolf. from Battletech/Mechwarrior. Its been around a while.. Anywho, i incorporated the two and came up with TimberJon.

About the wood.. with my experience, only solid woods here. everything from hard to soft woods. but not MDF. or any kind of fiberboard. drywall.. but obviously cant use that for an enclosure. (maybe as a dampener.. hmm)

I read somewhere there are different MDF grades. Should i just use particleboard? or is there a high grade MDF out there? I dont want to be worrying about stripping screws.

paikiah
04-29-2004, 10:14 PM
Solid rubber you say? That might just work wonders.:):) I might actually have to look into that too. I guess if they are of the exact same height, you an just say strips of it, and then tighten the bolts down. SUre, the bolts will be directly on the chassis, but the rubber blocks would have greatly absorbed the rest, so I think that might be the way I'd choose.

Ok, I see about your timber origin. :)

As for MDF, I think MDF and particleboard is a lil different. DO NOT USE particle board. They will slowly, but surely, break on you as time goes by. From my experience of MDF, there seem to be some diff depending on where it is made. It's mostly color, although some seem to be really poorly made. My rule of thumb is, the lighter the MDF color, the better. I've tried both a dark one and a light one, and the dark one just seem to be particleboard in MDF guise.

Thre's HDF wood, but apparently, it is too heavy and cubersome to use. Some people use cherry oak or something, I forgot..some real expensive wood. I say stick to MDF, cheap and you can always make another panel if something goes wrong.

If you've had experience with wood, then MDF is a breeze. Just think of it as thick paper and you're cutting it into pieces. Very easy to cute, with the right tools.

TimberJon
04-30-2004, 12:49 PM
If i have the room, thats what im going to try to do. But not solid blocks.. the criss crossed pieces. they flex in every direction except down. one could hold the weight of the entire box im pretty sure. so it wont squish down. if it did, then itd just be wiggling in every direction a few inches.. and thats unacceptable. By floating it in this way i would imagine more bass response, because the box has a little elbow room so to speak. Its like putting your finger on the cone of your driver while its trying to drive. take your finger off and you get your bass. anywho.. this is all theory in my head. if it doesnt work, ill just unbolt the pieces under it and try something else.

Now, to clarify the bolt idea. Im not planning on using bolts. Im going to try to secure the braces to the false floor, and the enclosure, with screws, or something else. I dont want the bolts going through all 3 pieces, because the only flex the bolts will allow will be up and down. and the rubberized pieces ill hopefully use will be useless if they cannot flex in all directions. (probably a 1/4" tolerance, N, S, E &W)

When the idea of building my own enclosure popped into my head, first thing i thought of was solid Oak =P so sue me...
If i used HDF, or some good Oak, i wouldnt have to resin the inner walls. Itd be solid enough. And ive heard a few home theater system woofer enclosures made of oak. they sounded good.

ok, all i gotta do now is get my hands on some good quality MDF. my boss says its hard to find. and i kind of gave him that look...
ill search around.

Ive SEEN MDF being worked on. looked relatively simple. on that woodshop show with the dude with the plaid shirt...

tools include, dremel, skilsaw, Table saw, dado saw, router + bits, cross-cut saw, other drills and etc... anything else i can buy.

paikiah
04-30-2004, 01:41 PM
TO be honest, I'm kinda lost with the rubber thing theory and the false floors. Until you try, you won't know what'll happen.

high quality MDF? Hmmm... home depot MDF is good for most people, plus they can cut the panels for you, which would be better than you trying to cut it with a jig. If you've got a table saw at home, then I guess buying a full size shheet (4X8) shouldn't be a prob.. but if yoiu're me and have cheap tools, then pre-cut slabs will be a blessing.

The list of tolls youmentioned, you mean you're going to BUY them to make a box? If you get it from home depot, then skip the tabel saw, router and stuff. All you need is a drill, drill bit, screws, a screwdriver (automatic ones will save you a whole lot of time and effort, or better yet, get a drill/screwdriver combo).

As for the sub cutout, I could hook you up with one, if you want quick holes done with a drill.

private message "Gauntlet", and he might be able to tell you his opinion about it, as I sold one to him about a week ago.

paikiah
04-30-2004, 01:44 PM
ok, here's a link to gauntlet's pics...

http://www.caraudio.com/vb/showthread.php?t=57559

TimberJon
04-30-2004, 02:52 PM
Of course. im going to test all my hairbrained ideas first. BUT, im not going to commit my trunk to a certain setup. Im trying to plan my ideas so that if they dont work they can be removed and replaced. I will probably test my enclosure with just the bottom of the false floor installed.

thats a go on the Home depot. ill take a good look at their stuff. light color, check.
i gotta car, so i cant buy it in sheets. so yea, ill have them cut it. the angled piece for the back of the box will be a toughie. especially for the ports, but ill figure it out. Im going to dado the upper and lower panels for the front and side walls only. that way the walls can sit down in the wood, which ill pre-goo before i set them in, then pre-drill, and screw in from the bottom. the braces i will probably affix to the upper and lower pieces, and dry-fit to make sure they all fit together.

TimberJon
05-01-2004, 12:58 AM
found this great site, before we started talking about the different grades of MDF. i only saw the MDF vs Particleboard pictures, i didnt know the cheesy one was particleboard. thats where i got the idea that there were different grades. learning quite a bit about box building from this site... ill share it with the other thread on box basics.

TimberJon
05-01-2004, 01:25 AM
found the JL shipping baffle. its 1/2" MDF just as i suspected... muwahaha...

TimberJon
05-01-2004, 01:43 AM
http://www.safeandsoundct.com/files/460x345/4_impalass09.jpg

looky this pic. While its not my system inspiration, its clean.
This is an impala SS. sucker has room in the trunk... my car really doesnt.
BUT, im confident i can fit a clean install in there with 2 W7s. this guy has 3 W6s i think. what really caught my eye was this huge custom MDF box for the subs and the amps. one huge sealed box for all 3 subs? hope he has braces in there! cuz i dont see any screws.

http://www.safeandsoundct.com/files/460x345/4_impalass08.jpg

how tall you think that box is? 4 inches? plus the vinyl floor another 1/4" max?
my poor trunk aint all that deep to start out with...

and holy hell. BMW 740iL (my cars trunk is nothing compared to this monster)
But still, should plan one of these up?
http://www.safeandsoundct.com/files/460x345/1_703_bmw07.jpg

paikiah
05-01-2004, 11:04 AM
the triple JL's look awesome. Ah yes, maybe he's only used glue to secure his box. A person here that goes by the name of ramos, he's actually carried out an experiemtn, to make a large box without the use of ANY screws. It worked, and supposedly worked very well.

As for the BMW box, look salright, although I'd much rather go for the conventional rectangular boxes instead. :) Oh, and try to look for bigbassman's car pics... now, THAT is what i call a box..a wall, in fact.

I don't recall you say what car you're going to install, but a lot of cars can swallow 12" subs without much fuss.

TimberJon
05-01-2004, 12:32 PM
Sounds like it would work. but the larger the box i would think the less the stress on the joints, so glue would work. the site for the impala and BMW pics is www.safeandsoundct.com

their complete system gallery shows some of the installs, including the impala and BMW.
can i get any ideas from them?

My install will be 2 JL 300/2's, 2 JL 1000/1's, 2 JL 12W7-3s, and i was going to get their 3 way component set.. but a good look at the 2004 buyers guide told me there are better component sets out there..

Of the sets im looking at, 2 i know to have great quality seem to be crossing each other off my list. correct me if im wrong, but heres why.

All have a tweeter, midrange, and woofer. i chose sets based on having those components, included crossover, and the largest driver being 6.5"
Do you know off hand if any of these sets' midrange drivers are larger than 4"?

Again, please correct me if any of these #s are wrong. I dont quite trust the magazine i got these figures from because many conflicted in other areas in the mag.

brand..........................model#..........MSR P(+/-).........max RMS
----------------------------------------------------------------
**JL............................XR653-CSI........570........................90
**Focal.......................165V3E.............7 29.......................160
Alphasonik..................PCT6551...........450. ......................175
Audiobahn..................ABC6003Q.........400... ....................320
Audiobahn..................ACIS63..............550 .......................320
Audiobahn..................ACIS62..............460 .......................200
Image Dynamics.........CSI.6MH............589........... ............200
Planet Audio...............V63CK...............279....... ................250
Swiss Audio................SAC650.............200....... ................120

paikiah
05-01-2004, 12:41 PM
Sometimes the best ideas come from making small models, which is what I did. I had plenty of thin scrap plexi lying around, so I "cut" them into panels and tried assembling them in various aspects. It helps a lot when calculating complex enclosures.

wow, dual W7's, and dual 1000/1. That's a LOT of power and a LOT of bass. There's another person on this site that has the same layout, although I forgot his login name. Awesome setup in his truck.

All the components that you've listed, I'm not too familiar with them. The JL and focal, yes, they are 6.5" drivers, I think.

On this forum though, the most popular components are CDT-61A's from www.thezeb.com They get the job done right, from what I've heard.

You don't need a three way component set. A lot of 6.5" and tweeter combo will give you delightful tunes. Also, be advised, you don't need a lot of power to run components.

If I were you, I would go with the W7's like you planned, the dual 1000/1, a single 300/2, and a single set of the CDT's or perhaps what I run, dynaudio.

SQ cars have speakers in the front, and with imaging, music must come from the front, and not from the rear. This is why I didn't talk about rear fill.

BryBrySmash
05-01-2004, 12:56 PM
http://www.jlaudio.com/subwoofers/pdfs/12W7_MAN.pdf

Look at thte bottom of page four. You cant go wrong with JLs recommended slot-ported box design for the W7. When I had my W7s in my '77 bronco, I used the sealed design that came with the sub. The only modifications to the plans that I made were making the MDF baffle 1-1/2" thick by laminating two 3/4" pieces together and using 1" MDF for the sidewalls. JLs ported design yields 1.75 cu.ft. tuned to 32 Hz. Dont second guess yourself by designing your own box. The works already been done for you by the manufacture so utalize it.

Bronco Install: http://www.jlaudio.com/Gallery/Installdetail.cfm?Action=3&Veh_ID=467

TimberJon
05-01-2004, 01:14 PM
What about Visonik component sets?

TimberJon
05-01-2004, 01:52 PM
http://www.jlaudio.com/subwoofers/pdfs/12W7_MAN.pdf

Look at thte bottom of page four. You cant go wrong with JLs recommended slot-ported box design for the W7. When I had my W7s in my '77 bronco, I used the sealed design that came with the sub. The only modifications to the plans that I made were making the MDF baffle 1-1/2" thick by laminating two 3/4" pieces together and using 1" MDF for the sidewalls. JLs ported design yields 1.75 cu.ft. tuned to 32 Hz. Dont second guess yourself by designing your own box. The works already been done for you by the manufacture so utalize it.


im not going to second guess the Manufacturer. Ive already had a nice email chat with one of the guys there at JL. Theyre quite helpful if your email is labeled correctly, and he offered to help me with the finals when i hammered out all my details.

The custom box im designing is meant to conform to the very back of my trunk. Im trying to save space, plus my car is the GXE model, which for some reason has a bump in the middle of the floor in the trunk while other models dont. SO i have to build my box around that, the largely curved backboard, and quite possibly the 6x9s that hang way too low.

Im probably going to double up on the front baffle. After thinking 1", and reading some other websites, like lungster, i decided to make it 1.5". laminating it and sealing it together isnt a bad idea... screws as well? I doubt i could find it at 1.5" thickness. I will call the MDF manufacturers listed on the Lungster site.

I have the manual saved to desktop since 02. Im not going to play with their power figures. Though Ngsm13 recommended 2 cubes per W7 ported, tuned to 26 hertz or 28 or something like that. Id like to find the middle ground between droning bass and punch.

My slots will be to JL specs, but might not in volume. I still have not gotten to how much volume i should put in my box. With all the bracing i plan to use, i will have to make the box bigger, by doing so i will try to make it wider. again, to conform to my trunk.