I have 2 MJM 18s and they are in a 12 cube 32 hz box oriented like this

okay im wondering if it will help at all like this

I didnt account for the Double baffle and the 3/4 sheet under the box to get it off my wires, and make it easy to move when i need to.

its about 3-4" away from the roof, and i swear all the sounds going outta the car LOL,

So will that help or hurt me

BTW its in this

it wouldnt work with the port like that id put the subs on top and have the port facing back

What is the problem with your original build?

What is the problem with your original build?

Its just so damn close to the roof, I didnt take into account to the double baffle for one

and then the subs are 3-5" away from the roof, LOL

I mean its fine i guess

I was seeing if that will improve anything,

It hammers on Lows like a Thunderstroms coming through,

and I also found a SEVERE leak, and FLex Issue today

Side panel moves about 1/4" in and out, and subs jump up about 1/8th inche

I didnt know MDF could flex like that :bigclap: thanks Mark for an awesome sub that can do that,

And use my Dowels I was supposed to put in the box from the jump

I wish I had dough for some IXLs

Do a New years Sale on them LOL

What is the problem with your original build?

Its just so damn close to the roof, I didnt take into account to the double baffle for one

and then the subs are 3-5" away from the roof, LOL

I mean its fine i guess

I was seeing if that will improve anything,

It hammers on Lows like a Thunderstroms coming through,

and I also found a SEVERE leak, and FLex Issue today

Side panel moves about 1/4" in and out, and subs jump up about 1/8th inche

I didnt know MDF could flex like that :bigclap: thanks Mark for an awesome sub that can do that,

And use my Dowels I was supposed to put in the box from the jump

I wish I had dough for some IXLs

Do a New years Sale on them LOL

Got-damn, must be something fierce

Got-damn, must be something fierce

Yeah LOL it was so much Noise before I rebraced it that I cut it off, and listened to wind Noise LOL, it was more Peacfull then the system, but im gonna take car of it tommorow

I just cant beleive that side panel flexes like that lol

If it was an IXL omg

I would be

have a sale mark lol

heres a box design i made it for my 18's

Edited November 7, 200816 yr by RobClay

you really need to brace that box if the side panels are moving that much. You are losing a lot of bass energy when that happens. If your box is that big, you may as well wall it off. Would you be able to fit the subs and port on one face if you did that? I can't imagine you couldn't, since it would seem that you have a lot more than 18" in height available.

Agreed. If you plan to rebuild, use plywood for the box and MDF for the bracing. I was chatting with a Civil Engineer friend about it, and he suggested the bracing material be MDF. Reason being is MDF is already compressed to extremes at its edges, which makes it excellent for stopping the box from compressing/expanding. There simply is *no* give there whatsoever. Where MDF fails miserably is in it's structural support (along the flat surface), which is the reason to use plywood instead.

All of my finished boxen will use this method from now on...

Ill be taking a wood structure class probably a year from now. Really plywood? I Would think because of bigger gaps between the pieces it would fail faster than mdf as far as bending stress goes.

Strength comes from fiber length. MDF has fibers that measure at best, a fraction of 1mm in length and are surrounded in glue. Since the structural strength is in the fiber itself and not the glue and the fibers are aligned randomly there is little strength.

Plywood however has very long parallel fibers, each supporting the other. On top of that, each layer of ply is positioned at 90* from the other, so you end up with strength in all four directions. Try breaking a ply board - you will notice how much it splinters verses a clean break with MDF.

plywood might be stronger but it is more flexible not a good thing try bracing a sheet of mdf and a sheet of plywood at the ends and stand in the middle the plywood will bend more. the flexability in plywood is also part of what makes it stronger.

Indeed, some plywood is more flexible but that is not because of the way it is made, but rather how dense the wood fibers are. MDF bends under its own weight because the wood fibers are very weak to begin with, are surrounded by glue and do not support each other. If MDF was structurally as strong as it is dense, it would be like concrete.

Of course, there is good and bad ply. Many folks here talk about 13 ply Baltic. That stuff is super expensive but superior in all respects. I like to use Fir as it is a hardwood and much denser than your standard Birch.

m

Well My next box will be a wall, Im getting it miced tonight on a Tl, so ill post the numbers, but I internal braced it with 1.5" wooden dowels on each panel no more flex and added some 3" drywall screws

Next setup 2 IXL 18s I realy want to try those bad

If you build the box right, MDF is just fine.

If you have walls flexing 1/4", no wood on earth of the same thickness would have helped you.

I'm not going to turn this into a wood debate, because this was never his problem from the start. If anything, it should be a construction debate.

I am simply amazed at some of the builds that get posted on here, and even more amazed at the praise they receive.

LOL if you brace the chit outta it, and resin it, it shouldn't flex so bad!.. hell even some redi rod might help

Unfourtunetly Its my fault, its how I did it, used too big a drill bit and they slipped out

When i test fit the screws, they held in well atleast I thought

Well I braced the panels thats fine, Now its the Port

Its jumping up and down now I need a Horizontal brace LOL

I just need to start over

Rush Jobs always expose there own Flaws

But Damn 95 honda you aint have to put me out like that

But your right

So.......you didn't use glue?

If you build the box right, MDF is just fine.

If you have walls flexing 1/4", no wood on earth of the same thickness would have helped you.

I'm not going to turn this into a wood debate, because this was never his problem from the start. If anything, it should be a construction debate.

I am simply amazed at some of the builds that get posted on here, and even more amazed at the praise they receive.

I'm sorry you feel that way. Everyone has to start somewhere, and a little praise here and there doesn't hurt. It's all a part of learning and understanding.

So.......you didn't use glue?

Yes I did, but it it hit the wrong part of board Hard to explain, but Its line dry glue where it supposed to hit the port

Yeah this is my second box that I have built ever, Not like im on here talking nonsense things happend and you do have to learn by doing, and put it this way

If you dont learn from your mistakes whats the sense in making them,

Dude I dont have money coming out my butt, or anyone in my area to realy help me on my builds so I just dove in and did it, and Im proud of it, and so is everyone else thats heard it, Until i got on the mic and it found another part to come loose

Im sure everyones build has been 100% and worked perfectly on the second go around with no help

I even put that Big box in the car by myself

It was just the way your last post was worded that made me think you didn't use glue. You were talking about the screws being stripped, but once the glue is set the screws don't really do much. The glue is what really holds the two pieces together.

We know most people don't have a ton of money to throw at it, that's why we get critical. We don't want you to repeat mistakes that you don't know you are making. There really should not be panels coming loose on an enclosure. If we didn't pick at this one and find out what's wrong, we can't help you avoid mistakes the next time. You may think that you know all of the mistakes that you made with this box, but perhaps not. I'm sure it's happened to a lot of us.

Perhaps some of us only used screws on our first box. Once we learned about glue, we made another box and used glue. But then oh we learned that bracing is a good idea. So we build a third box that has bracing. Then we find out that doubling up the front baffle helps a lot too. So our fourth box we double up the front. Then we learn about something else and make a fifth, sixth, seventh box, etc. We just try and get you to go from that first to that seventh box without all those wasted boxes in between.

:bigclap:

KU40

You hit it dead on, Im learing about Bracing, I didnt do it on my last box for my TREO TSX,

Did a double baffle on this one, help quite abit.

I should be done with it this time, think I fixed all the Issues with it.

Thanks for you guys support even though one apple tried to spoil the bunch,

"but once the glue is set the screws don't really do much. The glue is what really holds the two pieces together."

yes thats right Ive heard that before, and thats what I did........... but

I didnt let it set........ too excited and wanted to get it in, thats what ended up happening plus the the drill bit issue

heres a box design i made it for my 18's

Pretty much same design I had LOL