I saw a site just recently where a youth orchestra (landphilharmonic, I think) uses intruments built from scrap found in landfills.

Duplicating all those instruments would indeed be hard. But you seem to jump from that to it being impossible or improbable to 3-D print a violin or to code a violin-sounds-synthesiser. To me that landphilharmonic showed much the opposite from it being hard to emulate instruments, to the contrary it seemed to indicate that you don't even need a 3-D printer, perfectly use-able instruments can be created even out of crap found in landfills, no need for special and possibly expensive 3D-printer-ink!

But nonetheless 3D printer code for creating all standard and umpteen non-standard instruments is something we should try to have.

And robotic arms for bending metal and working wood etc should be able eventually to use landfill materials too, they just would need a feedback process of some kind letting them try the tone, adjust the object, try the tone etc, "tuning" it until it sounds as good or almost as good as the ones the landphilharmonic uses.

Also plans and instructions and guides for humans on how to find suitable things in landfills and how best to adapt them for musical use would also be good to have.

-MarkM-