A photocopy of "Koraal-Prelude op. 'Placare'" was given to me years ago by a guy who was a self-taught organist. He could not play this piece, but said it was "THE most beautiful piece he'd ever heard!"
It looked tricky on paper because of the 5-flat key signature, and didn't make sense because of the odd registration, which I did not understand at the time.
I'd never really played it, but kept it in the same book with the "Veni Creator Partita" that I just uploaded. I figured that I'd give it a try....
WOW! I LOVE this piece!!!
It calls for Strings 8' & 4' for the accompaniment, but on this performance, I used the Unda Maris & Salicional of the Positif. The melody calls for a Cornet of 8' 4' 2' 1 3/5' and 1', but I used the Cornet Vrks of the Recit, adding the Flutes 8' & 4' to it. The Pedal uses Foundations 16' & 8'.
Now the cool part, the part I didn't understand, is that the Cornet is to be coupled (for melodic) phrases to the Pedal, but at 4' pitch.
The way I did it was to play the Recit Cornet at 4' pitch, but an octave lower, thus, being able to couple it to the pedal at correct pitch.
The melody, "Placare," is actually "Placare Christus, servulis," ("To thy poor servants, reconciled") and is a hymn for Matins and Vespers on All Saints' Day.
Also, I did not realize that Dupre uses this same melody in "Le tombeau de Titelouze," - a MUCH harder piece!
This piece just enthralls me, as it uses the 8th mode Gregorian Hymn in close overlaps. I don't think it's a canon. What makes it so unusual is that the RH and Pedal are playing essentially at the same pitch, and it makes for wonderful sonorities.
This work is also in the "Cantantibus Organis" collection, but is in Volume III.
It may not be "the most beautiful piece I've ever heard," but the color and wonderful mysticism surely make it a VERY sweet little jewel!