Both machines are on display at a museum in Germany. Volunteers have iterated on MMX to the point where is can play music https://www.smmk.de/marble-machines.html

Where are the external drives living? Hard drive make their own noise. Might consider going with solid state if you want silence.

One example of this that’s making the rounds: https://www.asustor.com/en/product/FS67

Funky! I love it. What’s the story on the DIY patch panel? Did you 3D print the chassis and then pop in RJ45 keystones?

Great tip on the rails!