Summary

This is a small speaker horn to redirect sound from your speaker by 90°. Turns a top firing speaker into a front firing speaker to make the sound from a small speaker easier to hear. The design is for a 3" diameter speaker, but is easily scaled up or down for other sizes.

I use superglue to attach small magnets to the mounting tabs so it snaps onto the steel case of my radios.

The photo shows a red colored variation where I scaled it down for a 2" speaker and squashed the Z dimension even more to make it more low profile.