Subwoofer Ring Extansion Mount

I´ve replaced a 40+ year old 200mm speaker on a selfmade PA-Speaker. However the cutout was oval and not round. Therefore only 2 holes covered the wood underneath it, while the other 2 original screws where drilled in a pice of cardboard, as a mount extansion.

So I created an extansion to propaply mount the speaker. The inner diameter is 184mm and the outer one is 236 mm. The holes for the speaker are at a diameter of 197mm and the new ones are at 225mm. I used a 3,5 - 4mm screw to attach the extansion to the speaker.

Since my printer is not so big and i wanted to safe some time, i did not print a whole ring. Also, I only needed 2 extansions for one speaker.

I hope this idea can help someone with a similar proplem or give the idea to crating extansions for diffrent speaker sizes.