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Thread: JBL B380 Clones

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    Senior Member christo's Avatar
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    JBL B380 Clones

    Here some picture of the JBL B380 Clones I recently finished. It was based on information contained in the 1983 “New Lows in Home-Built Subwoofers” article.

    URL: http://www.lansingheritage.org/html/.../1983-subs.htm

    I was using the B380 build as a test run (carpentry and finishing techniques) for building a 4344 so some of the things I did may seem overboard for a subwoofer box.

    I used ¾ MDF for all the panels with a Baltic birch bracing 3 x 1.25 inches.

    Speakers are 2235s newly re-coned which when you add up the cost of acquiring and re-coning sure makes for a pricy pair of speakers. And add two more for the 4344s…nothing cheap about this vintage stuff at all.
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    Senior Member christo's Avatar
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    I started out with white birch veneer which I stained black for the baffle.
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    Senior Member christo's Avatar
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    The bracing I locked together by leaving a 3” gap for the next brace to slip in to.
    One of the most usefully tools I picked up for the project was the some metal 90 degree corner braces which allowed for the dry fitting prior to gluing. Not cheap but indispensable.
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    I used a table based router to rabbit all the edges and down the center of all panels where the internal bracing will be installed.

    I also did all the 4344 panels at the same time; it was a long day at the router table.
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    Senior Member christo's Avatar
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    The box is now together with the internal panel bracing installed. With each piece of bracing locking together and recessed the box very tight.
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    What I’m doing here is drilling the dowel holes for the cross braces that runs between the baffle the back panel. Set the panels face down together, place the straight edge at the correct height, measure equal distance in from each edge and drill the holes using the Dowelmax jig. This tool makes tricky stuff a breeze I highly recommend this tool. http://www.dowelmax.com/
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    Senior Member christo's Avatar
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    And in the next picture everything lines up, good thing as the front baffle had already been veneered, strained and had the first layers lacquer applied – no room for error.
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    This shows the dowel pins installed with the cross brace and a more complex use of dowels for the grill frame corners.
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    Here are the stands built out of Baltic birch and using the Dowelmax jig to drill dowel holes on the 45 degree face of each piece. Getting these pieces to close up once the glue was applied a nightmare as I could not close the gap with pipe clamps I had to use a 5 pound mallet to gently hammer them together.
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    Another use for the 90 degree metal corner braces, keeping the stands square while the glue dries.
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    Senior Member christo's Avatar
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    Here are the stands with the recessed holes drilled for the bolts used to attach the stands to the box. Burned my drill out using a large forstner bit doing this, That Baltic birch is ridiculously hard when going through the side of the laminated layers.
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    Back panel and fiberglass installed now time to mount the baffle and cross brace.
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    Excellent! More inspiration to get my ass in gear. I don't know what I'm waiting for. I have everything I need to completely build my 4345s. I was going to have the cabs built decided I'll probably end up regretting that so here I am. Beautiful speakers btw.

  14. #14
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    I used a long threaded rod to pull the back panel and baffle together. Since I was the designer I made sure the Speakon connector hole and port lineup to allow me to do this.

    Lesson learned here - I used way too many dowels to attach the baffle.
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    And now I had to cut the dowels off with a one-sided saw.
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