This series contains Hellmuth Wolff’s correspondence files. Subseries i contains correspondence between Wolff and various organ builders in English, French and German, primarily related to Wolff’s editorial work for the for the International Society of Organbuilders’ ISO Yearbook 1993, which spanned four years from 1992-1996. Subseries ii contains workshop documents, including opus lists.

The Correspondence series contains cards and letters to or from Paul Pedersen.
The series is arranged chronologically by time period as indicated. The series includes correspondence of special note to and from Murray Adaskin, István Anhalt, John Beckwith, Helmut Blume, G. C. B. Cave [Gene Cave-Browne-Cave], Mary Cyr, Joan E. Foley, Robert S. Prichard, Charles Reiner, Edward Schreyer (Governor General of Canada), R. M. Schoeffel (University of Toronto Press), John Weinzweig, etc. Additional correspondence, detailed in other Finding Aid series, is also listed below.

The Clippings series contains clippings, articles and reviews from newspapers, journals and magazines concerning performances of Pedersen’s compositions as well as McGill University Records.

The Photographs series contains photographs of church organs, professional photos of Donald Mackey alone and with others. Also includes correspondence from Helen Mackey to Cynthia Leive.

The Scripts and Writings series contains writings, lectures and talks by Donald Mackey; as well as documentation pertaining to special projects organized and carried out by Donald Mackey (i.e. organ installations and events). The series is organized chronologically.

The Compositions series contains compositional documentation, 48 original compositions, 14 arrangements, and numerous untitled sketches. The compositions are organized alphabetically by uniform title, with a separate subsection entitled the “Bach Gamba Project”. Composition dates, durations and instrumentations are provided when possible.

This series consists of copies of the correspondence with agencies and others concerning Sonde musical pieces, performances and recordings.

The Audio Recordings series contains 2 audiotape reels and 3 compact discs. Including recordings of Donald Mackey and the Renaissance Singers of Montreal in concert and CBC radio programmes.

The Miscellaneous series contains miscellaneous documentation pertaining to the Renaissance Singers of Montreal. Documents in this series are organised chronologically.

This series contains audio recordings of twenty interviews conducted by Dr. Helmer as well as music of George Adams. The series consists of 22 compact discs and 4 cassette tapes, for a total of 26 items.