A-7 mods
Replace stock drivers with JBL-2226 and BMS 4550.
Replace lower vent panel with one having 4 , 4 inch dia ports, 5 inches long.
Pic #60
Reinforce 15” horn flares, glued in with construction adhesive not wood glue or epoxy.
I used boards which were 5 ? inches by 12 inches with one side cut to a 20 degree angle to better mate with the horn flare.. These are way too live.
Shown in pic # 62
Before and after is shown in measurement, gets rid of a few dips.
Optional, it wouldn’t hurt to put a 2X2 diagonally on the lower cavity side walls with a 2X2 added to tie the sides (from one side to the other) together.
I would use construction glue to adhere the 2X2’s to the walls and when dry, use screws to attach the cross brace.
Apply damping to the under side of the final bell of the 511 (not visible).
Mount the horn on the rear side of the wood, setting it back from stock.
Mount the 15’s with an extra front gasket for clearance at Xmax.
Use foam tape to seal all removable panels and replace the wood screws with 1 5/8 drywall screws.
Drizzle some extra glue at the front edge of the flare on the interior (the glue joint at the front where the bent plywood attaches. Use that gorilla glue (polyurethane) for this as it fills gaps. On this one there was a gap in the wood (on the inside).
Remove and remount the horn mounting board, remount 2 ? inches rearward and use the foam tape under it (which dampens the box top panel)
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