Down or up?

One of the messages that comes across clearly from reading Berger's book on memory and medieval music is that musical instruction in the middle ages (at least for church music, for which instruction manuals survive) was heavily dependent on memorising many mnay examples of 'standard' forms, or musical formulas. In a natural relationship, the music itself can be recognised as often consisting in the re-usage and re-composition of these forms, rather than 'original' composition as we might conceive of it now.

A flip-side to this is that certain alternative 'forms', although they might seem equally conceivable and reasonably interchangeable to the modern musician, were simply not part of the vocabulary.

For example, many medieval tunes end with a sub-final to final progression (e.g. if in D-dorian, ending with F-E-D-C-D). But many instruments, particularly drone instruments such as the hurdy-gurdy, have a tuning set up such that their lowest note is the final, making this progression impossible. Modern players then tend to substitute the tone above the final, e.g. F-E-D-E-D. But this is not an ornament found in medieval music (to our knowledge), and probably would have stood out like a sore thumb to musicians at the time. Much less obviously wrong would be to play, for example, F-E-E-E-D, as a simplified form of the melody, particularly if other instruments or singers are simultaneously providing the correct progression.

Probably the best way to absorb such 'principles' is just to play lots of the (correct) melodies, so that the forms become second nature.