building a cab. material to use, bracing, etc

Discussion in 'Amps and Cabs [BG]' started by jock, Mar 12, 2003.

  1. jock


    Jun 7, 2000
    Stockholm, Sweden
    Can you guide me to a site or give me some tips of how to build a basscab. I have the volume and dimensions covered. What I wonder is what to use, Plywood? How to brace the cab. What type of joints to use etc.

    Rock on:bassist:
  2. ESP-LTD


    Sep 9, 2001
    Use the Search For Keyword: feature at the top of the page. "Cabinet Building 101" was a good thread.
  3. 19mm MDF is more stable and less prone to buzzing. It is also significantly heavier than Baltic Birch or Apple-Ply void-free plywood. The MDF is 3.82 kilos per liter. The void free plywood is typically 2.49 to 2.96 kilos per liter.

    Simple butt joints are entirely satisfactory if you take the time to install cleats (glue blocks) at all the joints. I glue and screw my butt joints together, then seal them with high quality Silicone sealant. I build from MDF so a simple X-Y-Z plane internal brace is sufficient. If you are going to use the lighter plywood, more bracing may be required. You will know for sure after you build it. Don't finish it until you have sufficient bracing installed.

    Buy a copy of "The Loudspeaker Design Cookbook" by Vance Dickason. It has everything you can possilby want to know about design, testing and building methods.
  4. Petebass


    Dec 22, 2002
    QLD Australia
    You may want to have a look at this website . Heaps of info.
  5. patrickj


    Aug 13, 2001
    Baltimore, MD
    Do you recommend 3/4" MDF over 3/4" Baltic Birch?
  6. Do you want solid or light weight. That is the choice.

    I transposed the numbers into Metric, so hopefully did not err.

    MDF is 49 pounds per cubic foot. A 4x8 3/4" sheet is exactly 2 cubic feet, or 98 pounds. Each of my subs took a full sheet to construct. Add in many screws, the driver, wiring, grille, more screws for the grille, and you have a 150 pound cabinet.

    Baltic Birch plywood is 32 ~ 38 pounds per cubic foot. Assuming 32 pounds, making the same cab from Baltic Birch plywood would save 34 pounds over MDF.

    I find MDF very dimensionally stable and easy to machine. It gives me very good results, so I put up with the weight. I'm preparing to build a set of four 1x10 PA cabinets with Delta 10s, but will do it from 1/2" MDF because they don't handle any bass. I don't think buzzing will be a problem, and I want the lighter weight MDF.
  7. Petebass


    Dec 22, 2002
    QLD Australia
    Both! I used plywood on mine. Plenty strong enough and they sound fine. Light weight was a big part of my design criteria, but I wasn't going to be satisfied with a flimsy cab. They've both taken plenty of abuse and show no sign of breaking up.
  8. patrickj


    Aug 13, 2001
    Baltimore, MD
    bgavin, you have any pics of some of the cabs you've built? (inspiration, etc)
  9. I don't own a digital camera, but I will be taking some film photos this weekend at a wedding. I'll snap some at the end of the roll.
  10. TxBass


    Jul 3, 2002
    Frisco, Texas
    I built both of mine (that get used a lot) with similar design as what bgavin describes. use plenty of bracing, sealant, etc. I did put a center brace in both cabs--in order to support/distribute the weight of both the cabs and the rack sitting on top.
  11. I just finished a pair of 1x10 that are over built.

    I used 3/4" MDF which was WAY overkill for this project. The 1x10 are for high frequency units in my bi-amp rig, and not subjected to bass pressures, so I should have used lighter material. Each 1x10 is 29 pounds empty, w/o grille. Heavy little suckers, for sure. No bracing except for the mandatory cleats at all joints. External dimensions are 10.25 x 11.75 x 20.75, and the cab is sealed. Using fiber fill stuffing, the alignment is pretty close to a D2 type, Qtc = 0.577.

    My daughter's band needs PA mains and monitors, so I'm going the other way and building some of the cabs from super light 1/4" material. Each main consists of two 1x10 (Delta 10b) and an Eminence horn/driver, for a total of three separate cabs. I'm going to do the horn cab in 1/4" plywood just to see how it works out. I figure the 1x10 Deltas will do OK in 1/2" material, and 12 x 12 x 17 inches external dimensions. I'll do the speaker board with 3/4" material. These won't be handling any bass, so they should be ok with light weight materials.