This is a quick tutorial about how to flush mount (recess/rebase) a large subwoofer driver; using a router and the Jasper Audio router jig. This technique is different than the one described in the Jasper instructions. It's slightly more labor intensive but doesn't require an expensive and difficult to manage 1-1/4" router bit. It also generates significantly less sawdust.
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1) Using a 1/4" spiral cut up twist router bit, cut an outer diameter circle that is the proper size for the outside of the driver frame. The depth of this outside cut should be deep enough to allow the driver to be flush with the baffle when installed.
2) With the same bit make second cut that's the diameter of the woofer cutout. The depth of this cut isn't critical. It should be at least as deep as outer cut, but shouldn't be so deep as to penetrate the full hickness of the baffle
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3) Next change to a 3/4" flat bottom carbide bit, set the cut diameter remove the material between the inner and outer circles. An accurate measurement isn't important here since, the outer circle has already been indexed to the driver diameter and depth, and the inner circle is the driver cutout.
4) Plow out the material in several passes to avoid burning the bit and or overheating the router motor.
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5) Finally put the 1/4" spiral cut bit back in the router and finish the driver cutout
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Sorry for the glare from the flash....
Here the driver was recessed deeper than usual due to the extreme height of the surround. The driver has a rubber cosmetic mounting ring. In this picture that ring has been removed to allow accurate marking of the driver mounting holes. That makes the outer diameter of the cutout appear oversized but it isn't. ____________________________________________________________________________