GoKawiil3D-printing a Trombone Building a perfectly playable plastic trombone for only $30
It’s that time of the year again: April Cools! My friend Ersei wrote a fun April Cools post two years ago, so I guess I’m joining that cult trend too.
Anyways, instead of the usual Lean propaganda, today’s post will be about brass instrument physics and 3D-printing a playable trombone!
Kublai: Whoa! I wanna hear it!
We’ll get to that soon. But first, some physics!
Brass instrument physics
Trombones are weird.
To play a wind instrument, you do some fancy stuff with your mouth which induces air pressure waves in the instrument. These waves have specific wavelengths that fit nicely inside the instrument’s tubing. For brass instruments like trombones, you vibrate your lips at some frequency like you’re blowing a raspberry, causing the air in the instrument to also vibrate loudly at a similar frequency.
The main distinction in instrument design is open tubes vs. half-open tubes, because any open end is forced by the atmosphere to be at constant pressure:
Harmonic Open tube Half-open tube Note (in major scale) 1 1 2 Nonexistent 1 3 5 4 Nonexistent 1 5 3 6 Nonexistent 5 7 ♭7 (out of tune) 8 Nonexistent 1
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