8" Subwoofer adapter for Stern Spike 2 pinball machines, possibly others

I swapped out the stock speaker in my Stern Godzilla, RUSH, and Iron Maiden for a Blaupunkt GBW801 subwoofer. Because these speakers are mounted INSIDE the cabinet (unlike a subwoofer box for a car stereo), they require something to lift it up above the bottom of the cabinet so the cone doesn't slam against the cabinet and speaker grill. This was the simple solution.

I have printed 3 of these. They will fit - just barely - on an MK3S surface. I also printed one on a Matter Hackers Pulse printer. That build plate is slightly bigger. I used PLA for both printers, 30% infill. The MK3S provides a better looking output but both are functional.

This print should work for most 8" speakers. Notice the 4 mounting holes are oval. This was done to give some angle allowance to the screws.

In order to use this adapter and mount a subwoofer, you need to remove the old speaker, knock out the factory studs that are used to secure the original speaker. Drill the holes slightly bigger and install 4, #6-32 T-Nuts underneath the cabinet. Create a sandwich starting at the bottom with your original grill, then the adapter, then the subwoofer. Using 1 ¾" to 2" hex or phillips head 6-32 screws, thread them through the ‘sandwich’ and into the T-nut. Gently tighten but not too much that you malform the subwoofer frame. When complete, you should be able to shake the entire cabinet by holding the subwoofer magnet and giving it a little shake.

Simple solution, required to make a sub work in a pinball cabinet.