Player pianos work via a vacuum, where air is sucked through a few pin points in a piano roll with a bellows. A series of pipes leading to each key translate these small holes into notes.

tracks need one, but when you're staring at that blank piano roll ... 1: Find your key The first step is to determine the key ...

A while back, [Jacob] played around with a player piano. After feeding a roll into the machine and trying ... resulting MIDI file isn’t in the right key, but that’s easily fixed by anyone ...