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MDF Sealer- Sub boxes

Discussion in 'Audio' started by wakedog, May 24, 2001.

  1. wakedog

    wakedog 1/2 ton status

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    What is a good sealer for mdf, medium density fiberboard?? Also what thickness should i use for sub boxes?? Thanks.
     
  2. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    A silicone sealer should be fine. Be sure to smooth it into all the corners and seams. Allow it plenty of time to dry (like overnight) before installing the speakers. While the silicone is 'curing' it outgasses some really stinky fumes...some people report that it can damage the adhesive on the speaker surrounds. Once the curing process is completed, there is no risk of this happening.

    As far as MDF is concerned....I would go for at least 5/8" and probably thicker. You will be building a LOT of pressure inside that box, and the stiffer you can make it the better it will sound. Also, don't just build a 6-sided box....try to put bracing on the inside of the box too, epecially to re-inforce the longest dimesions of the box. Anything you can do to ruggedize the box will help it to be stiffer and sound better. Don't forget to glue the joints before nailing or screwing them together too....

    Overkill is the key to a strong, and good sounding enclosure. Good luck and have fun [​IMG]

    -Greg72
     
  3. Prembird

    Prembird 1/2 ton status

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    3/4 in. medite will work really good... its a highly compressed partical board... and to add to the other post... best if you have atleast one angle in the box... where the subs are or the back panel... doin this will get rid of standing waves...by doing so it will releave alot of back pressure off the subs and it will also avoid cancelation... basically it will sound a little better.. adding some type of poly fill to the box is a good idea also. i agree with the bracing inside the box and seal everything before you screw it together... dont use nails... sealer should be between each board before screwing them together... also go over every joint inside the box with sealer... install braces and seal around them also...(better safe then sorry)... if you plain on running a port in the box then make sure you seal around those as well... as for size of port and length... that depends on what frq. you want to obtain... personally i would use a sealed enclosure. But the size of the wood you use really should be considered by what size subs you are goin to run..... 8 dont need as thick of a board as 12's... or do what alot of peps do.. go to your locale stereo store and buy a prefab. box... cheap, already sealed, easy to install... and you dont make a hell of a mess when doin it... just an idea... hope it helps


    Prembird

    If it aint loud then turn it up!
     
  4. wakedog

    wakedog 1/2 ton status

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    Thanks for the input. My plan was to make boxes that go in to the side panel in the rear behind the wheel well. And there will be a sub on each side, the sub will be angled up a little if u know what i mean. I am going to be using 2 alpine type r 12" subs and the enclosure will be sealed. ANymore help would be great. THis is my weekend project. Thanx
     
  5. CaptCrunch

    CaptCrunch 1/2 ton status

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    Hey wake... I have some custom made boxes I made up myself just like this. They look great, but too little space for 12's... I'm going to be switching to 10's

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
     
  6. Prembird

    Prembird 1/2 ton status

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    when building the box you need to remember what the spec's on the subs are for enclosure size.... I good rule of thumb is 1.5 cubed feet for a 12.... some subs can runs under that... check the specs.. it will tell you how much space you need for a sealed enclosure... sealed boxes take less air space then ported ones do... just something to think about...

    Prembird

    If it aint loud then turn it up!
     
  7. CaptCrunch

    CaptCrunch 1/2 ton status

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    Well my boxes are basically made to go over the wheel wells and are kinda a L shapped box. They came in about 1.25 which I feel is a bit too small for my DVC 12's. Reg 12's maybe ok as they generally seem to need a bit less air space then the DVC's. I'm looking for a different set of subs and may just make a new box for 10" subs. 3/4" MDF sealed w/ silicon... grey carpeted. Man they look sweet and match the interior like they were stock.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
     
  8. wakedog

    wakedog 1/2 ton status

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    Well my subs are supposed to have 0.7-1.0 cubic feet per sub so i think i will be fine on the space issue.
     
  9. DBLAZER

    DBLAZER 1/2 ton status

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    I have said this before and I will say this again, A sub box is not rocket science. standing waves, .000005 cubic feet, being that specific really does you no good. Richard Clark, one of the pioneers in this buisness and many others have always said that building a stereo in a car is absolutely the worst enviroment you could concieve of to put music in. There is glass that reflects sound, carpet that absorbs. Plastice that colors and well you get the point. Build the enclosers to the recomended specs or as close as you can get. Build them out of MDF. Dont worry about the rest. Now if you are building an SPL machine then yes, you need to take into consideration all the other little details like standing waves and the like. OK well, just my opinion. See ya

    [image]http://www.darkknight.ca/images/dklogo.gif[/image]
    http://autotronixcaraudio.com
     
  10. Ddragggon

    Ddragggon 1/2 ton status

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    MDF is nice, and what I'm building my sub box out of. a lot of audio companies have the specs for the speakers included with the speakers when you buy them, and MTX has a site online with all the specs in it, and a couple of reccomendations for tuned boxes. the setup I'm curently building will fit behind the middle seat in my suburban, with the subs pointing back, and the ports pointing at the roof. I hae to agree with DBLAZER's commenarty on the matter: there's just no real good way to cram a good stereo into a car. no acoustics, and no airspace for the soundwaves to fully develop. this is why I'm putting Pioneers in the doors, instead of Infinity Kappas, or infinity anything. I just need something that sounds Decent over the noise of my straitpipe/glaspac/incomplete exhaust 454.... I currently have 2 whole Pioneer 6x9 4 ways (last years model) sitting in the middle seat, pointing at the roof, and it sounds hella better then most stereo's in these things.... I can't wait till I finish setting up the subs, and door speakers.... of course, I don't have any time in comparison, although I just learned that Monday is some sort of a holiday, and I have the day off, and PAID! so, I might have time to get some of that stuff thrown together.

    -Rich
    1977 C20 suburban
    454/400 trailering special
    Planned stereo:
    4 MTX 4000 series series subs (2 10's, 2 12's)
    4 Pioneer TSA1655 6.5 2 way speakers in doors,
    2 pioneer 4 way 6x9's mounted to rear roof, pointing forward ( mounting ideas?)
    pile o' amps
    new head( dunno what yet)

    Visualize an atlantic 442 Steam engine running at full tilt here...
     

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