This series contains files pertaining to the radio series that Richard Coulter wrote or produced, and is divided into 16 subseries. A complete subseries for a particular radio series could include:

• Scripts.
• Correspondence.
• Cost sheets, requisitions (studio, personnel, instruments, equipment, scores, etc.), contracts, payment information and other production information.
• Other files, including publicity, promotional information, press clippings, concert programmes, libretti, etc. Note: Composer identification is omitted for concerts of works composed
  before the twentieth century and all item counts of five or greater are approximate.

The Montreal Mendelssohn Choir donated eight volumes of choral sheet music from the Choir’s library in 1895, a year after the Choir’s dissolution. There are only seven extant volumes in the collection because volume 6 has been missing since at least the 1980s.

This series consists of photographs with Sonde event number indicated if known.

The Audio/Visual Materials series contains 97 slides, records, audiotape reels, and digital audiotapes (cassette) and CD.

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.

This series contains the print copies of journals and conference proceedings in Hellmuth Wolff’s library. There are some annotations on several of the issues. The works are listed in two separate bibliographies in Appendix 1: Periodicals/Journals Bibliography and Appendix 2: Conference Publications Bibliography.

This series consists of photographic negatives.

This series contains print copies of published monographs of various languages. The works are lists in the bibliography in Appendix 3: Book Collection Bibliography.

This series consists of public posters advertising Sonde performances, with the Sonde event number added to the verso of the poster.