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Speaker Cabinet Materials: Beyond MDF

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  • Max_Andrews
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    I'd use hurricane nuts from the rear rather than threaded inserts - way easier to install and stronger too.

    Leave a comment:


  • sbrtoy
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    Great replies to this, lots of new thinking generated...

    Mark, one question on the HDPE...what if it was used as a hybrid material with another like aluminum and you drilled the panels and glued in threaded inserts then screwed the panels together and sealed from the inside? Do you think it would hold the threads if the proper glue was used?

    Also I loved the Mini Look-alikes, really nice looking speakers!

    Leave a comment:


  • philiparcario
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    put a 1/2 inch or 3/4 piece of mdf as the meat in a plywood/mdf/plywood sandwich . do it for at least the baffle. all other places 2 plys and braces will do.

    Leave a comment:


  • brijenjas
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    I've been reading this thread with interest as I will be making a Sub box soon.

    I read where one poster suggested using MDF and plywood together.

    This weekend while reading the sale papers, I noticed Menard's has some premium plywood with MDF core listed.

    Has anyone tried this type of plywood with the MDF core?
    Does it even sound like it would be worthwhile to use?

    Should I just use two 1/2" plys glued togetether as I originally intended?

    Thx
    Bri

    Leave a comment:


  • philiparcario
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    concrete backerboard would work.

    from the inside to the outside.

    mdf/glue/rubber pond frabric/mastic/backer board/mastic/tiles

    nice look. any tile you want even marble. just hard to cut a circle in the marble.

    Leave a comment:


  • tpremo55
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    Has anyone ever considered concree backerboard or any of the similar heavy dense materials to back tile installations? I'd figure a couple of layers of that with a layer of damping in between would be quite effective.

    Leave a comment:


  • mgrabow
    replied
    http://www.woodcraft.com/family.aspx?familyid=3958

    is very consistent but try gluing veneer to a phenolic face... So why go through the trouble when MDF works so well. "if it aint broke, don't fix it"

    Leave a comment:


  • Mark H
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    Having built quite a few boxes out of HDPE for the fabs at Motorola I can tell you that HDPE is not actually glued together, it's welded using a thermoplastic welder. The industry standard welder is made by a company called Seelye.http://www.seelyeinc-orl.com/index.html. Harbor Freight also sells a cheapie but it only comes with a tip for plastics like pvc.

    http://www.harborfreight.com/cpi/cta...emnumber=41592

    In addition to a set of several different expensive welding tips you of course need a good router or two and a fairly large air compressor that can keep up since your essentially have a large leak going when using the welder.

    And the obligatory bottle of isopropyl alcohol to preclean your joints.

    It takes alot of practice to gain the skill to weld plastic properly but using HDPE would make a great speaker box or even using translucent PVC. I've considered selling small 0.75 - 1.0 cf cabinets but they would be expensive to build with 3/4" to 1" material. They would however be water proof though.

    Leave a comment:


  • marlboro
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    pvc. See Calipso's below, using PVC pipes for the midranges.

    Leave a comment:


  • audionut71
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    Max, you rock!

    Now I have to get off my a** and figure out how i'm going to do this.:eek:

    I'll keep everyone updated!!

    Stan, get over here NOW!!!!! I can't carry this stuff downstairs by myself!:D

    Leave a comment:


  • Max_Andrews
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    Well the great thing about acrylic/lexan/polycarbonate is that the glue to use is the same for all of them: http://www.eplastics.com/Plastic/Lex...carbonate_Glue

    It's a solvent glue, so it actually chemically joins the two pieces together creating a very airtight and strong bond. You want the #40 "epoxy" type or the #16 "syrup" type and not the #3 thin liquid type because it's likely your edges will not be perfect and the thin glue will not be sufficient to bridge the gaps. The #40 is stronger but takes a lot longer to set and I think the #16 will be sufficient.

    The #16 glue sets VERY fast, within five minutes.
    The #40 glue sets in about an hour.

    When you glue, use corner clamps, but don't over tighten them. You want to keep the glue inside the joint and not force it out, which will leave you with a big mess. Also don't use too much glue. It should be brushed on thin and just enough to cover the surface, not a thick bead like it's OK to do with wood glue. You have to remember that with plastic glue it's actually melting the plastic to itself, and the glue itself has no structural properties and almost completely evaporates during drying. I'd also run a bead along the interior edges to ensure an airtight seal.

    Leave a comment:


  • audionut71
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    at the risk of thread-jacking...

    If i do get this 1-1/4" mystery bullet proof material cut and machined properly, what is the proper adhesive to assemble it with?

    Just make sure to put a driver in there that is worthy
    I think I have that covered... Stay tuned for a write up on my current sub. It uses a custom built 15" driver that I happen to have 2 of...bwahhhaaahhhh (evil laugh)

    Leave a comment:


  • fbov
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    May I ask, then, if plywood and MDF are preferred materials, any ideas for making them "better." I'm making a pair of 70l NatPs with three horizontal braces at 1/2, 1/3 and 1/5 points and I see a need for more, if only to connect the centers of the flat areas inbetween, plus top and bottom.

    Bracing addresses cabinet effects by damping low order modes but it seems to me that added panel mass will reduce cabinet contributions further by driving down resonant frequencies to those damped by the bracing.

    Any thoughts?

    I do have access to large quantities of ferrite beads and epoxy ....

    Have fun,
    Frank

    Leave a comment:


  • Max_Andrews
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    Originally posted by audionut71 View Post
    I am dreading starting this project, because I am sure that I will make some mistake and destroy the material.
    No guts, no glory! Like Bob said, do a few tests on an edge to see if your method is going to work. If you can pull it off, you'll have a ridiculously dead sub box! Just make sure to put a driver in there that is worthy

    Leave a comment:


  • Jonathan Anspach
    replied
    Re: Speaker Cabinet Materials: Beyond MDF

    There are two disadvantages to boxes. The first is the resonance of the box. Enough mass and/or bracing can reduce or eliminate that, but then there's the second problem, which is reflection back through the cone. You can stuff the box to reduce that, but you can't eliminate it completely at the low frequencies that would excite the box resonances. So you need to decide if going to all that effort to make the box ultra-stiff is worth it to only treat half the problem.

    Leave a comment:

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