I've thought about adding a single-octave xylophone to a regular
88-note player before, but I didn't know how to change the roll to make
it play that.  Someone mentioned A-rolls, so I tried to search the web
for definitions/specs of an A-roll, but the search engine ignores the
hyphen and gives me results for "a roll", which are many, and not
relevant.

Is it common practice to disconnect the top 12 tubes and run them to
the xylophone, then modify a roll to play those notes, or does this
"A-roll" already have notes cut for other instruments?  Thank you.

Bill Mackin