I'm asking this in the rather specific context of me being a non-performer (due to physical disabilities) who wishes to "humanize" the midi files I create using software such as Finale and Logic Pro.
For brevity's sake, let's limit our discourse here to piano playing, and then consider only pieces from the romantic era, in a slow tempo, with a single, gently undulating cantabile-like melody over block or arpeggiated chords (the "Lied ohne Worte" style).
My understanding so far is as follows. I understand that there are many, many exceptions to any "rule" in musical aesthetics, but I'm only looking for the most general of guidelines.
- When beginning a phrase, it is often appropriate to subtly slow down the tempo.
- Towards the middle of the phrase, if it has some sort of temporary climax there, a very slight accelerando is often in order.
- The higher a note is pitched, the louder it is played. Again, with many exceptions.
- When a series consists of notes of equal length, you linger just a tiny bit longer on those that are harmonically and/or metrically important.
- Phrases usually begin softly, then get a bit louder, and end softly again.
- The accompagnement is generally played softer than the main melody, but occasionally gets louder if the chord in question has much forward harmonic "momentum" (a Neapolitan sixth for example).
- Melody notes that belong to the same harmony are generally played molto legato. The gradation of legato across harmonic transitions depends on the level of attractive force between the chords involved.
Any modifications or additional guidelines would be much appreciated. I'm also looking for quantitative data in all of this. What would be a nice distribution of note velocities (on a scale of 0 to 127) for your typical cantabile phrase, for example? I had one that began at 40, then rose to about 80, and subsided to 40 again. It sounded nice and "human"-like, but a bit too obvious and theatrical. Does the curve generally need to be flatter?