Rotating wall speaker supports

I wanted to mount speakers to the wall next to my projector screen. Instead of buying a new set of speakers, I repurposed my good old Edifier R1700BT and designed a rotating mount to screw them to the wall (upside down so they face a little bit downwards)There's a wall part with a 12,5mm hole and a speaker part with a 12mm dowel. You have to print them in this orientation for optimal strength: Each speaker requires 2 sets of mounts, one above and one at the bottom to spread out the forces a little bit more. This makes them suitable for a variety of speakers (as long as they have a strong wood frame). As you can see in the pictures the speaker with the power cord required the mounts to be a lot further apart due to all of the cables. Because I had to mount them to a concrete and a brick wall, I didn't want to drill so many holes close to each other so I mounted the brackets to a strong birch plywood board (painted white for uniformity) which I first anchored to the wall with two