Hello all, I am new to the forums. I am actually in the process of making a player piano, mixed electronic and mechanical. I am going to use traditional player rolls, but replacing the vacuum valves with electronics.

My question is, how far apart are the holes/"notes" on a standard roll of music for a player piano? So far I have not uncovered any information on this thus far, and wanted to work on certain pieces revolving around that before I receive my rolls. Thank you all in advance!

Standard 88-note rolls are perforated 9 to the inch. Older 65-note rolls are 6 to the inch. If you wand exact dimensions you will have to give me a little time to go measure a tracer-bar.

With very few exceptions piano rolls are 11 1/4" wide. Holes for 88-note rolls are spaced about 7/64" on center. The first note perforation on the left end is 11/16" from the edge. Anything further to the left is a control peroration.
I should point out that WurliTzer did this about 35 years ago using very small pistons behind the tracker-bar to operate switches. Worked fairly well, but the roll-tracking mechanism didn't quite cut it.