This version of the M8a-MKIII is designed to use the WoodStyle 803Rev enclosure. The box has external dimensions of Height-19", Depth-12" ,Width-10". It's constructed from 3/4" stock. As received the box is nicely built but lacks the fundamental stiffness we prefer. It will be significantly braced and reinforced.

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We start the box 'building' by stripping the paint off the rear panel. I used a nontoxic water based stripper. The blistered paint  is removed with a razor scraping tool. The panel is then sanded to roughen the surface for good adhesion when gluing on the new back panel. These 803Rev were received with a factory cutout for an input plate.

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A piece of 3/4" MDF is cut slightly undersized. The edges are beveled at 40 degrees, this makes the panel less visible on the completed speaker. The panel was attached with TiteBond II and secured by brad nails.

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Gluing on the new back brace covers the input plate cutout. Once the glue has set, the input plate cutout can be opened using  bearing under router bit inserted through a starter hole. The bit follows the stock hole cut in the factory design.

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At the stage the modifications to the back of the cabinet are complete, and it's ready to be painted.

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Next a 1/4" Masonite panel is cut. This will raise the tweeter and help eliminate destructive interactions between the tweeter and the stock 3/4 grill cloth frame. Paint stripper has again been used to remove the paint where these panels will be attached. It's attached with glue and nails. This panel is used as a template for making felt tweeter diffraction pads. These are detailed later in this article.

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Extensive modifications are made to the interior of the enclosure. Photo detailing these would be difficult given the small confines of the interior of the box. As a result they are itemized and can be seen in the photo below.

1)  The sides of the boxes have 3/4" MDF laminated to the stock panels. Numerous pieces are cut slightly smaller than the woofer opening. They are inserted, slid into position, then glued/nailed in place. 

2) The front baffle is reinforced with 3/4" oak. Strips of 1"X3" and 1"X2"oak  are cut and glued until the entire baffle is covered. 

3) A piece of 1/4" Masonite is cut to fit the backside of the front baffle. It covers an area above the woofer and behind the tweeter. This forms an enclosure for the tweeter, and provides a place for gluing in a damping pad (see picture and text in Part2 ).

3) Next an oak 1"X2" is cut and glued to the new MDF sides. This oak piece is mounted on a diagonal and it's length is 1/2 the height of the box. It's placement is such that there is clearance at the top and bottom of the cabinet for the crossovers. This piece stiffens the box and creates attachment points for side to side bracing that will be added later.

Note: the woofer must be recessed flush with the front baffle when using this stock box. If it isn't,  the edges of the driver frame will interfere with the grill cloth frame.

The front and back are now ready to be painted. Then final assembly can begin.

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Click HERE to go to Part 2