Most people engaged in research about Welte will know about
Peter Hagmann's Ph.D. dissertation published in 1984:

  "Das Welte-Mignon-Klavier, die Welte-Philharmonie-Orgel und
  die Anfaenge der Reproduktion von Musik"
  (C) 1984 Peter Lang AG, Bern;
  ISBN 3-261-03464-5

Hagmann was one of the first people who researched Welte after the
reproducing piano system nearly fell into oblivion in the 1960s and
'70s.  Unfortunately, the book is long out of print.

The Freiburg University Library has made it available again on their
document-server:   http://www.freidok.uni-freiburg.de/volltexte/608/

 [ File: hagmann.pdf (2,082 kb) ]

Thanks to Dr. Raffelt from the library for his initiative and to
Dr. Hagmann for the permission to publish the book this way.

Gerhard Dangel
Augustinermuseum
D-79098 Freiburg

 [ Born in Basel in 1950, Peter Hagmann studied musicology as well
 [ as German and French literature.  His 1982 Ph.D. dissertation is
 [ "The Welte-Mignon piano, the Welte Philharmonic organ and the
 [ inception of music reproduction".
 [
 [ Hagmann studied organ and in 1978 received his teacher's diploma.
 [ From 1982 to 1988 he was director of the music collection of the
 [ public library at the University of Basel.
 [
 [ In 1989, after several years as a freelance writer and music critic,
 [ he became the full-time fine arts editor and chief music critic of
 [ the newspaper "Neue Zuercher Zeitung", and in 1996 he became editor
 [ in chief.  In 1990 he was awarded the "Critics Prize" from the
 [ avant garde festival, "Steirische Herbst" (Styrian Autumn), of Graz.
 [
 [ More at
 [
http://www.kug.ac.at/schubert/english/jury/Lied/lebenslauf/lb-hagmann-englisch.html
 [
 [ -- Robbie