ESTERDAY, I chose to attend the breakout session led by Charles Cole in Christ Church Cathedral. The topic was how to accompany chant on the organ for which Charles gave us a number of “rules” to follow. He also acknowledged that not all of these rules must always be strictly followed.
First among the “rules” is the need to stay within the notes of the scale pertinent to the mode. Also, as in all composition, parallel octaves and fifths are to be avoided. Cadences, too—both perfect and plagal—are not advisable. Registration and harmonization, we were taught, ought to serve the melody and text (which are always paramount in chant), striving to remain unobtrusive. It seemed to me that the underlying thrust of the presentation was this: a skillful organ accompaniment can actually help to reveal facets of modality within a particular chant.
During the session, a question was raised about the Bragers Kyriale. This is one of the many resources made available for free .pdf download here at Watershed. The volume provides accompaniments for all the Ordinaries, Credos, Asperges & Vidi Aquam, various ad libitum chants, etc. It is even available in a high key and low key version. Check out the following links for more on the Bragers resources available here:
Bragers Kyriale Accompaniments
Bragers Gregorian Accompaniment Treatise