mattgrayyes, (edited ) 
I made a pair of 1U Eurorack speaker modules this evening.
I ordered a couple of 20x40mm speakers, and some panel mount mini jack sockets.
While waiting for them to arrive, I modelled a 1U panel in Fusion360 (this was my first parametric design)
With the parts in hand, I measured them up and designed a mounting bracket for the speaker and some bracing around the mini jack hole.
Put it all together and amazingly they seem to work as planned first time!
