HELP - Design of sub box (size, shape, finish)

Discussion in 'Archived Threads 2001-2004' started by Cam S, Apr 10, 2002.

  1. Jim A. Banville

    Jim A. Banville Supporting Actor

    Joined:
    Jun 20, 1999
    Messages:
    652
    Likes Received:
    0
    Seems to me that as long as the area between the end of the vent tube and the back wall of the box are at least equal, you'd be okay. I'm haiving the same issue. I'm building my box for the 12" Shiva I plan on ordering in the next couple of days. My box is roughly 23" x 23" x 13", measured internally, minus the space taken up by the driver, amp and port.
     
  2. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Quote:

    "Seems to me that as long as the area between the end of the vent tube and the back wall of the box are at least equal, you'd be okay."

    Equal to what Jim??? BTW, how much volume did you account for your port taking up??
     
  3. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
  4. ThomasW

    ThomasW Cinematographer

    Joined:
    Nov 6, 1999
    Messages:
    2,282
    Likes Received:
    0
    I use either Wilsonart 'Figured Mahagony' or Nevarmar 'Rosewood'. Those two are the most real looking of all the laminates
     
  5. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Of the Wilsonart, I like the Montana Walnut, and the figured Mahogany, very nice grain.

    how thick should the laminate be for using on a sub box??
     
  6. ThomasW

    ThomasW Cinematographer

    Joined:
    Nov 6, 1999
    Messages:
    2,282
    Likes Received:
    0
    Buy post forming aka vertical grade. It's the cheapest. If you want to make it look even better, put on a coat of ArmorAll or similar material when you're done
     
  7. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Vertical grade hey, ok I'll try and find it. The armorall is that the stuff for making vinyl and plastic parts on your car shine???
     
  8. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Ok guys, I picked up the 4x8 sheet of MDF today as well as a 4x8 foot piece of Wood Grain Laminate.

    I have 2 questions.

    First, will 3/4" mdf be strong enough for this 23"Lx16"Wx22.5"H ported box??? I'm not to sure if it will be. Should I double up the MDF on the front baffle, where the port and driver will be mounted?

    Second, I bought a 4x8 foot piece of Formica in a Wild Cherry wood grain with the Artisan finish. It looks really nice, but the only thickness I could get at the price that I paid (FREE!) was "general" thickness. Will this be a problem? My box will have straight edges, with no rounded ones, so I won't have to worry about bending it around any curves or corners. But will I still have to worry about the thickness??

    Also, how important is it to recess the driver into the MDF?? If I kept the front baffle to only 3/4" I was worried that there wouldn't be a lot of wood to mount the driver to if I recessed it.

    thanks for the help guys, I'm gonna start putting it all together this weekend, and I'll take lots of pics with my digital during the buildup.
     
  9. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,128
    Likes Received:
    0
    Definately don't recess if only using 3/4" mdf. Doubling up the baffle definately wouldn't hurt anything. Unless you really want to for cosmetic reasons, there is no performance reason to recess the driver. In fact not recessing it may be better.

    Are you going straight off of one of Adire's schematics? If yes good, if not take a look at them and use them as a model for how to properly brace the enclosure.
     
  10. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Dustin, I'll only double up the front baffle if it is really needed for strength, but this MDF is pretty dam strong.

    The box volume will be around 95L and tuned to 22hz or so using a full length FP4 kit.

    As for bracing, I was thinking of using two peices of MDF mounted vertically inside the box, with holes cout out in it for the port and a few other random holes for air flow.

    Will that be good enough for bracing, or could I go about bracing the box in another way like 2x2's or something like that?
     
  11. ThomasW

    ThomasW Cinematographer

    Joined:
    Nov 6, 1999
    Messages:
    2,282
    Likes Received:
    0
    Cam

    MDF is heavy, but it's not very strong. Use double 3/4" for your endcaps.

    Want to check for strength? Hold a piece of MDF out in front of you and hit the edge with a hammer, it will break. Do the same with a piece of ply and it will dent.
     
  12. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
  13. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Can anyone help me out with the laminate part??
     
  14. Pete Mazz

    Pete Mazz Supporting Actor

    Joined:
    May 17, 2000
    Messages:
    761
    Likes Received:
    0
    Standard grade laminate is easier to work with, IMO. You don't have to be concerned about a perfectly flat substrate or filling holes, etc. The only downside is the thickness of the edge of the laminate that you'll see, but with a woodgrain(darker) color it'll be inconspicuous.

    Pete
     
  15. ThomasW

    ThomasW Cinematographer

    Joined:
    Nov 6, 1999
    Messages:
    2,282
    Likes Received:
    0
     
  16. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    I managed to get this stuff for free (saved 73 bucks!) cuz I had done alot of computer work for a friend who own's a renovation company.

    As for prep, I prolly won't have to worry too much about imperfections in the MDF. I'll probably be using brads and wood glue to hold it all together then I'll put the Laminate right over top of it.

    This stuff looks sooo nice, it saves me the time of staining veneer is is WAY more durable.
     
  17. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,869
    Likes Received:
    0
    For constructing the box I suggest using glue and a nail gun (if u have one). (Also, too much glue can cause the MDF to warp) Then drill countersunk holes next to the thin temporary nail gun shots and using screws. I suggest putting the screws at least 2 inches away from the ends of the wood to prevent splitting.

    After that, fill up the screw holes with bondo and use an orbital sander to smooth out the bondo.

    Other tips I had to learn the hard way:

    * It is real easy to warp untreated MDF

    * pre drill holes to prevent splitting

    * Use clamps where you can if gluing the MDF

    * Remember to cut off about 2 inches from the edge of the main sheet of mdf if you use an end. This helps prevent warp and provides freshly cut (clean) edges.

    * caulk inside cabinet and speaker terminal

    (I assume that when the sheet is in storage, the ends absorb moisture so by cutting off the "old" edges you have a fresh sheet.)

    Good luck
     
  18. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Thanks chris, I have a nail gun and will be using brads, and those combined with a little bit of wood glue on the ends of the MDF to be joined provided a good solid joint on the speaker box's I built for my computer speakers. When you say the MDF may warp if untreated, are you talking about when I apply the contact cement onto the MDF for the laminate?? If the contact cement will warp it, which I doubt it will, what do I use to treat the MDF??
     
  19. Cam S

    Cam S Screenwriter

    Joined:
    Jan 11, 2002
    Messages:
    1,524
    Likes Received:
    0
    Well, I built my box today, and man, it was ALOT harder than my smaller computer speaker box's were, I guess since it was much bigger, and more room for error. The box ended up being 16" wide, 22.5" tall, and 23" deep. I think i may have made a BIG mistake in not putting any sort of bracing inside the box, because when I knock on the side it makes a really "tin can" sorta noise. I've the entire box glued together, and all the holes cut for the driver, amp, and port. How could I make it so the box is a little more "dead" when I knock on the side of it, or is this not a problem??

    AHHH man, I'm stressed
     

Share This Page