Announcement

Collapse
No announcement yet.

First try for a subwoofer enclosure

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • First try for a subwoofer enclosure

    Seeing as I don't have a spare tyre but I do have a ****ty subwoofer, i'm going to replace it.

    So today I carved out some of the foam in my boot to make an area as big as I can.







    I'll be putting a Memphis 12" Shallow sub in here, the enclosure should be just about right, 1 sq ft.

    The top will be 3/4 inch MDF, and sub will be inset a little bit.


    So being a complete n00b with this fiberglassing thing, how much do you think i'll need?

    I was thinking maybe

    5 square metres of chopped fiberglass matting
    4kg polyester resin

    I know you make the fibreglass 'bowl' first, with a couple of layers, let it dry and pop it out. Then you reinforce it with a few more layers, until it's all good.

    Then cut the MDF to size ready to go on top. I guess i'll need to make sure I have room around the edges of where I want it to fit in the boot, considering i'll be putting extra width on when I glass the MDF in.

    Unfortunately in Australia we don't have 'bondo', so I assume normal (or reinforced) body putty would be fine for putting around the inside of the sub to seal up / reinforce the edges of the MDF.

    If i'm going off the track already, feel free to steer me in the right direction

  • #2
    no spare tire, yikes, but i would use something like construction subfloor adhesive inside the box to fill in the gaps. bondo is too stiff, even though it might work. PL400 is wicked stuff, you could actually use it to hold your box together without screws.

    Comment


    • #3
      They give you a can of goo and a compressor instead of a jack and spare tyre. But I have roadside assist anyway (AAA equiv).. i'm not that keen for DIY

      Comment


      • #4
        I don't think there's such as thing as PL400 in Australia either. Almighty Google was hard up for some relevant search results.

        Comment


        • #5
          Ok with the MDF top, should I get 3/4 inch MDF and use a router around the edge of the sub hole so it's inset flush, or should I get 2 thinner panels of MDF and join them together, with one hole slightly smaller than the other (so essentially the same thing)?

          I guess i'll have to put some vertical bits of MDF in to brace the top slightly too.

          Comment


          • #6
            if you glass in strategic pieces of MDF to screw the top down, that works well.

            don't forget to put dowel or thick rope in the bottom to make the box strong - otherwise it flexes a lot with the sub-bass pressure.
            MacMini in an Alfa? - Why not!

            Comment


            • #7
              Thanks for the tips, I actually read a couple of posts today and saw the rope trick.
              Also the base of my boot isnt flat, its got a star in it which will actually help with the strength ironically

              Comment


              • #8
                Originally posted by MaXius View Post
                Ok with the MDF top, should I get 3/4 inch MDF and use a router around the edge of the sub hole so it's inset flush, or should I get 2 thinner panels of MDF and join them together, with one hole slightly smaller than the other (so essentially the same thing)?

                I guess i'll have to put some vertical bits of MDF in to brace the top slightly too.
                You're better off to go with a single piece of MDF, but you could use two half-thickness parts if you glue them together over the entire joined area. That's the only way to get close to the strength of 3/4 inch material; screws alone wouldn't do it.
                .
                If just enough is really good, then too much ought to be perfect.

                2006 Scion xB with in-dash Atom & Lilliput 889GL -- Worklog at http://www.mp3car.com/vbulletin/work...res-links.html
                .

                Comment


                • #9
                  Thickest I can find so far is 16mm.. have to ring around a bit more to find a place with thicker.

                  Comment


                  • #10
                    have you looked into making a aperiodic membrane sub box?
                    I see yo cutting foam trying to make space bigger, this could solve that. Just my thoughts =)
                    Car: Ford Focus
                    Currently stock setup. Trying to decide on the best setup for me.

                    Comment


                    • #11
                      Originally posted by jellymonster View Post
                      have you looked into making a aperiodic membrane sub box?
                      I see yo cutting foam trying to make space bigger, this could solve that. Just my thoughts =)
                      This is the first i've heard of aperiodic membranes, but now i'm googling it. Have you had experience with them?

                      Comment


                      • #12
                        nope, I'm kinda doing the same thing as you soon so I've subscribed =P

                        mine however is going inside the spare wheel so is going to be even smaller.

                        From what I've gathered it's basically making a small sub box sound like a big one
                        You basically get foam, squash it between two grills and theres your aperiodic membrane.

                        Also if you want you can measure the impedance curve to see if you have too much or too little foam.
                        Car: Ford Focus
                        Currently stock setup. Trying to decide on the best setup for me.

                        Comment


                        • #13
                          I am a fan of fiberglass, cause I've been working with it for quit some time now, but really I'm a bigger fan of getting the look and sound I want with the quickest turn around. Being that your shape is pretty regular, I wouldn't do any fiberglassing at all. The only reason I see to use fiberglass is to create a finished complex surface. Your not doing that here. You're going to have a flat floor finish. I'd say make a box, mount your sub, make a finish panel and route the edges around the sub so that your sub is "in-layed". Clean, quick, no waiting for resin to dry, no hoping it will hope up to the stress.

                          I know it won't maximize the area like a perfect mold but are you really losing enough square inches to justify the work involved in prep, glassing, sanding, painting, etc... to justify the fiberglass route.

                          Comment


                          • #14
                            Originally posted by MaXius View Post
                            Seeing as I don't have a spare tyre but I do have a ****ty subwoofer, i'm going to replace it.

                            So today I carved out some of the foam in my boot to make an area as big as I can.







                            I'll be putting a Memphis 12" Shallow sub in here, the enclosure should be just about right, 1 sq ft.

                            The top will be 3/4 inch MDF, and sub will be inset a little bit.


                            So being a complete n00b with this fiberglassing thing, how much do you think i'll need?

                            I was thinking maybe

                            5 square metres of chopped fiberglass matting
                            4kg polyester resin

                            I know you make the fibreglass 'bowl' first, with a couple of layers, let it dry and pop it out. Then you reinforce it with a few more layers, until it's all good.

                            Then cut the MDF to size ready to go on top. I guess i'll need to make sure I have room around the edges of where I want it to fit in the boot, considering i'll be putting extra width on when I glass the MDF in.

                            Unfortunately in Australia we don't have 'bondo', so I assume normal (or reinforced) body putty would be fine for putting around the inside of the sub to seal up / reinforce the edges of the MDF.

                            If i'm going off the track already, feel free to steer me in the right direction

                            I say go for it. But remember, the resin will eat through that tape, and cause a mess , and the parts it wont eat through will get very hot and cause a mess. I would put another layer of something between the first coat and resin and tape. Also remember when you pull it out (if you can get it out) you will not have the exact same shape when you finish the box, stretching cloth will pull the sides in but not a big deal on finished product. Also get a bottle of MEK and a roller to roll the resin out of the fiberglass and watch for pooling. If I was doing this ( I love glass) I would cut the bottom out of 1/4 MDF to fit, and fiber glass to that. If you can bring in the sides at all from your design, you will have an much better time of getting this out of the car when it is dry.

                            Comment


                            • #15
                              If you do go the fiberglass route. Mask the area with low stick masking tape (the blue or green tape) then get either foil tape which you can find in the ventilation/duct work section of Home depot or get some 3m adhesive spray and your normal cooking foiling. Spray the dull side of the tin foil then slap it on the masking tape. That will be your chemical (resin) barrier. Then get turtle wax and wax up the tin foil then buff out the residue,... that's your mold release.

                              Whether you go with the box or the fiberglass, good luck and good building.

                              Comment

                              Working...
                              X