With the FDM-printed prototype version there's a noticeable "a mechanism is occuring" sound, largely due to layer lines. Tbh it's not too loud rn but I'm confident we can get it smooth and whisper-quiet using any vaguely sane manufacturing technique (defaulting to injection moulded ABS but we have some options). The marbles/roons themselves are silent, it's just a question of getting the barrel cams to play nice.