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Theorized and proven: "KABLAMM!!!"

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  • Theorized and proven: "KABLAMM!!!"

    When the Eminence Definimax 4012ULF came out earlier this year (May I think), I thought the specs looked just insane for a 12" pro-sound driver. Essentially, it's the 12" LF with the motor from the 18" LF attached. McJerry said we should build it when I showed him a simulation of what this idea was capable. The Bl for a single is 27(!!!), and a pair will anchor a sensitivity of 97dB and a 4 ohm load. F3 is near 25Hz anechoic in this 4 ft^3 box, and room gain will allow even lower reaches.

    Initial simulation:


    Xmax at 400W each into a pair of 12":


    I wanted to keep the box relatively compact and resonant free. I also wanted it to serve as a multi-purpose platform. Home Theater vs Live Sound applications specify MDF or plywood respectively for construction, and I used MDF. (Note: If using as an HT sub, the infrasonic filter of most plate amps at 20 Hz will prevent any mechanical problems from becoming a possibility. Xmech is large enough anyway that bottoming the drivers will be a rare occurrence.) I went with an opposed dual 12" approach to cancel vibrations, and braced the box really well. I wanted to keep the port straight and use it to help brace the monster, and that was the main factor in shape as well as application. Being that it required a round port of nominal 8" diameter, the length required to tune to 28 Hz is 31.6" long. Obviously, I converted dims to utilize a slotted port. The initial premise was to have ball-casters on the back of the box so that it was easy to roll around to where it would be positioned, and then laid down where it was finally placed. The port was to be a handle paired with the Dayton Audio branded corner handle on the other end. Being about 100 pounds as an estimate before building, ease of use was a requirement. 2 people can easily carry this, but it is awkward, and the casters make it much easier. I drew this up in MSPaint to get the rough layout:



    The dims are all pretty close to spec except the length.

    3x 1.25" dowel supports brace the port structure so it doesn't go BONG during operation.


    I also used "I" shaped braces from side to side and double-3/4" thick baffles to keep the driver mounts from flexing.



    I added cross-braces into the ends of the box before I glued on the ends. The end with the corner handle has an angled brace to allow the handle to fit easily. In the ends of the box, since it called for 'heavy fill' to get the response right, 1 pound of polyfill is loosely inserted, and the top and bottom of the woofer area is lined with acoustic finger-foam.



    You can tilt your head and see the dimensions of the cutouts used:


    ...as well as the position of the driver mounted center:


    There ended up being about 4" between the woofers magnets, and I flushed the frame of the driver while leaving the gasket proud.


    To assemble the box. I constructed the port first, with the 3 supports, to be the main anchor during assembly; glued and screwed. All exterior holes were cut after construction. Side one was laid down after doing all of the biscuit cuts and a dry fit of all the panels. Screw the inner baffles for the woofers to the sides during the dry-fit process, and glue them down with a circle of glue. Panels are 13.5" square. I next laid down the line of glue and the biscuits for the port, followed by the I-braces, the top (or bottom, depending on use), and the other side panel placed on top finishes the 'braced square tube' portion. I then clamped and let dry, ensuring the ends all mated well and at the same length.

    Once that was dry, I used some 3" wide MDF strips for the end cross-bracing. I physically marked the boards without measuring real inside dims at the actual length using the box's end dimensions, and then cut 1/16" large on purpose for both side to side and top to bottom on both ends. Then, using a technique learned in 8th grade for a shadow-box, I notched one of the boards for each end with a 3/4" wide slot, about half-way through the width of the board. I knocked out the 'finger' with a hammer, and routed the remaining appendage away. The second board will slide half-way into the first since I did not notch it as well for strength's sake. Being that I had them measured via box to fit tightly, I used a rubber mallet to tap them into place for a check. You may have to round off a corner on one end of the board to get it to go into the box at first, but they do insert relatively easily. Tap back out to remove the pieces, apply glue to the cross-junction and the places the boards will be after installed, and then tap back into place. I placed glue above the joint on the vertical walls so it flowed to the right place as inserted, and I left one of the boards flush with the end of the box to help the ends glue up better. The braces took me about a half hour to make and install- this was so slick I'll be doing that this way again!!

    Being that I did not have bar clamps long enough to encompass the 37.5" cabinet length, I had to use the strap-clamps for the ends. I first cut for biscuits and dry fit, then glued and clamped by 2 straps- one around the top and one around the bottom. I used a 'keeper' screw into the end cross-braces to keep the panels in place while affixing the straps. The glue and biscuits aligned the rest. The small holes are to identify the port placement and make a handle until all the other holes are made. (Edit: Someone asked about the straps. I don't know the brand name, but they are $20 at Woodcraft. Rockler sells a similar version in metal.)


    Biscuits and glue hold it together throughout. I used the circular saw to cut for the handle, 1/2" R roundover to match for all of the hardware, 1.2" CL 45 degree chamfer to add some character to the edges. A Router Buddy circle jig cut the holes and recesses, and the miter saw cut the bracing as well as other necessary parts not requiring the table saw.

    Matt (the final recipient) gladly paid for the materials to construct this behemoth. He had the box sprayed with Line-X before attaching all of the hardware. He drilled the hole for a D-Series Neutrik Speakon through the longer end of the corner handle with a stepper bit, as well as adding black steel corners, rubber feet, H-Nuts, and machine screws for the drivers.

    There are feet on both the top and bottom for a reason. When carrying it, the port is at the top, and if need to set it down comes- you need feet on the bottom as if it were carried. Tip it up to the casters on the end, and roll it into position. Then either lay it down as you carried it, or with the port on the bottom to couple with the floor and position the speakon on the lower rear.

    I can see pairs or triples stacked on either side of a stage, or a single in an HT being a force to be reckoned with. It performed well at CKY-DIY, as I had hoped it would, and Matt really likes it! It can also likely fit inconspicuously behind most living room couches with a close rear wall.



    Later, and thanks for looking!
    Wolf
    Last edited by Wolf; 11-19-2015, 02:36 PM. Reason: Clamp info...
    "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
    "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
    "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
    "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

    *InDIYana event website*

    Photobucket pages:
    http://photobucket.com/Wolf-Speakers_and_more

    My blog/writeups/thoughts here at PE:
    http://techtalk.parts-express.com/blog.php?u=4102

  • #2
    Re: Theorized and proven: "KABLAMM!!!"

    Nice work, Ben! I believe that is the largest speaker I've ever seen you produce!!

    Comment


    • #3
      Re: Theorized and proven: "KABLAMM!!!"

      Wolf,

      This looks amazing...or insane...your choice. The first photo looks a lot like an underground parking garage I was recently in. ;)

      If ever my wife and I decide to live in Indiana, I'd really like to live in your neighborhood - just not next door. My wife would likely divorce me if we lived next door. You're an inspiration.

      Michael
      Meniscus Audio Adelphos (awesome!); GR Research LGK full range

      Comment


      • #4
        Re: Theorized and proven: "KABLAMM!!!"

        Wow - 118 dB without exceeding xmax at 25 Hz? wowza.

        I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
        "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

        High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
        SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
        My Voxel min sub Yet-another-Voxel-build

        Tangband W6-sub

        Comment


        • #5
          Re: Theorized and proven: "KABLAMM!!!"

          Would you say this speaker is punchy? ;)

          That's an interesting speaker. The cabinet isn't huge either at 55L/driver. It's not common for a pro-audio driver to sacrifice sensitivity for low end extension, usually the answer for deeper low end is to get a bigger speaker. A friend of mine just got a pair of Lab15's (to compliment an Adire Tumult if you can believe that), I'll have to run the sims to see how the lab subs compare to this monster.
          "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
          exactly a Fc 3K for both drivers, anybody can do it." -Xmax

          Comment


          • #6
            Re: Theorized and proven: "KABLAMM!!!"

            GREAT job Ben !!!!!!!!!

            Thank you for tackling this and for documenting your project so well !!!!

            Sounds great !

            McJerry

            Comment


            • #7
              Re: Theorized and proven: "KABLAMM!!!"

              Oh that thing is amazing. I'd be afraid for my plaster walls!

              Comment


              • #8
                Re: Theorized and proven: "KABLAMM!!!"

                You only built one? ;) just kidding!

                Looks very nice and professional!

                Do you plan to use it at home or some sort of PA use?

                Comment


                • #9
                  Re: Theorized and proven: "KABLAMM!!!"

                  Having been an early listener of Wolf's sub at the CKY-DIY, I can say that it is impressive.

                  Now I need to figure out a way to build a lightweight version that can be moved by just me.

                  Jim

                  Comment


                  • #10
                    Re: Theorized and proven: "KABLAMM!!!"

                    Wolf, nice job. Do you know how Matt plans on driving it ?

                    Comment


                    • #11
                      Re: Theorized and proven: "KABLAMM!!!"

                      Originally posted by Jim Griffin View Post
                      Having been an early listener of Wolf's sub at the CKY-DIY, I can say that it is impressive.

                      Now I need to figure out a way to build a lightweight version that can be moved by just me.

                      Jim
                      Airloy X100 aerogel should do the trick. Might be a tad expensive.
                      It is estimated that one percent of the general population are psychopaths - New Criminologist: Understanding Psychopaths

                      Comment


                      • #12
                        Re: Theorized and proven: "KABLAMM!!!"

                        Originally posted by Pete Basel View Post
                        You only built one? ;) just kidding!

                        Looks very nice and professional!

                        Do you plan to use it at home or some sort of PA use?
                        That's only because I got the other pair I will be building a dual box version
                        https://www.facebook.com/Mosaic-Audi...7373763888294/

                        Comment


                        • #13
                          Re: Theorized and proven: "KABLAMM!!!"

                          Originally posted by marvin View Post
                          Nice work, Ben! I believe that is the largest speaker I've ever seen you produce!!
                          This is the largest one-piece project, and second largest overall I've built. The Marianas is 6.5 cubes, but it's collapsible.

                          I ensure you- there was a lot of groaning and grunting to make my cuts on this big thing. I'd make biscuit cuts on one end, and then have to move it 180 degrees to do the other. The table saw was priceless in terms of having a surface to work on.

                          Thanks,
                          Wolf
                          "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                          "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                          "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                          "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                          *InDIYana event website*

                          Photobucket pages:
                          http://photobucket.com/Wolf-Speakers_and_more

                          My blog/writeups/thoughts here at PE:
                          http://techtalk.parts-express.com/blog.php?u=4102

                          Comment


                          • #14
                            Re: Theorized and proven: "KABLAMM!!!"

                            Originally posted by Squidspeak View Post
                            Wolf, nice job. Do you know how Matt plans on driving it ?
                            He's talking about getting a Drivecore 2 and utilizing the bandpass filter setting. That said- he has plenty of amplifiers as it is....
                            I honestly feel someone could run this off of a 100W plate amp for an HT if wanted.

                            Later,
                            Wolf
                            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                            *InDIYana event website*

                            Photobucket pages:
                            http://photobucket.com/Wolf-Speakers_and_more

                            My blog/writeups/thoughts here at PE:
                            http://techtalk.parts-express.com/blog.php?u=4102

                            Comment


                            • #15
                              Re: Theorized and proven: "KABLAMM!!!"

                              Originally posted by isaeagle4031 View Post
                              That's only because I got the other pair I will be building a dual box version
                              Ah- you left out one detail-
                              It was too sensitive to use with another project of yours, so you had to go with something LESS efficient. LOL!

                              Later,
                              Wolf
                              "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                              "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                              "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                              "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                              *InDIYana event website*

                              Photobucket pages:
                              http://photobucket.com/Wolf-Speakers_and_more

                              My blog/writeups/thoughts here at PE:
                              http://techtalk.parts-express.com/blog.php?u=4102

                              Comment

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