I need to build an enclosure that's 37x37x37inches. I'm going to use MDF I’m not sure what thickness. I'm really confused about constructing it. Could I just do mitre joints or am I going to have to build a frame and build around it?
You can use 3/4" if you add a little internal bracing. I would seriously consider using 1" MDF however, and possibly for an enclosure that size, if it will be used at high output levels a pair of 3/4" sheets glued and clamped together to make 1.5"
You can use miter joints if you like. That may be the best bet for a nice brushed or sprayed finish, if you are skillful with the cuts and careful with the construction. You can build around a frame if you like. What I usually do is just plain old butt-joints, where the hardest part is subtraction and addition to get the panel sizes correct.
wel i for mine i did 3/4" mdf and rabbeted the sides if i spelled it right i took a router and cut about halfway through the thickness of the material on the edged and it i so strong i could stand on it with no bracing and screws about 2" apart mine was 30"L*13"W*10"D
I use butt joints backed by a bracing strip, and also find it easy to make a mistake with the maths.
After building a box too short, I wrote some software to help me prototype different box sizes and then print my cutting list. I've used it on a few subs now and find it very handy - I think others will too.
Apparently it's frowned apon to post links to yourself in messages, so if you want a copy, see the site details in my profile - go to "Free software" and download "boxnotes". The page also has a link to online instructions.
Note for you Yankees - you will have to work in metric - its a lot easier do the maths to adjust by 1 or 2 mm rather than increments of say 1/64 inch.
I kinda like that.... Alot of people say Americans.... but America is not our country, it is the United States of America. America IMO is collectively the continents of north and south america which would make anyone living on those continents "americans." For some reason it is rarely seen that way and people from Canada are called Canadians, people from Mexico are called Mexicans, blah blah blah, you get the picture. No one calls some one from Canada an american, or at least I've never heard of it. So why do we from the United States get labeled american. Seems wrong to me.... Yankees, now everyone knows that the Yanks are from the U.S.A.
Back to the thread topic.... Unless you're a good woodworker, miter joints are tough to get perfect. Building an internal frame is a very good idea to get a very ridged box that will not have panel flexing. Use at least 3/4 inch MDF if bracing is less than every ~7 inches and/or if the driver in question is capable of over 105db maxSPL
I'm from the U.S. but don't call me a %#@& yankee !!!
Waste your time and money if you want using 1" or 2 3/4" layers, but you still need bracing anyway. Shelf bracing is best and with an enclosure that size, I'd use 3/4" material and 3 shelf braces with 3 perpendicular cross shelves if I was going for the gusto, but 2 would probably be sufficient.
atnaat, your box will have a side to side resonance of around 190hz. Being a cube, you get this times three!
Worse though, is the driver-to-rear-wall res of about 98hz. I would definitely add some treatment. Especially to the wall behind the driver!
My tip would be to make the box less deep and make the width not equal to the height. Spread the pain!
maybe we are called american because we are the most powerful and one of the first nations to be established as a "nation" in the america's. and since we are the United States of AMERICA, being it is part of our name...american is just short for that. Australians are called australian even though the contenential australia consists of more than the contry, the country and the surrounding islands
im not a yankee, yankee's are northerners. i e people from the north east the civil war is still wadgeing.
On topic, good bracing is theadrod, and 2 layres really dont too muhc over one layre painted with polyester resin. 3/4 (19mm) painted with polyester resin and braced with 5/8" threadrod is very strong