Question: Great Web Site!
I am studying the Bach B Minor Invention BWV 786. In the Explication, the manner of execution of the trill is very clear, and yet one can find conflicting interpretations in the recordings and in edited manuscripts.
It seems that most performers allow themselves creative liberties in regards to ornamentation. Is this a valid practice?Mike (Dallas, Texas, USA)
Albert's reply: This is a really great question (and thank you for the kind compliment!). Ornamentation in general is an enormous topic, and musicologists have written thick tomes on ornamentation in different stylistic periods or dedicated to a single composer such as Bach or Mozart.
In fact, my own teacher Paul Badura-Skoda wrote a 570-page book titled Interpreting Bach at the Keyboard, which covers ornamentation in detail.
To answer your question in general, yes, there's a certain amount of creative liberty which performers can use. However, there are many instances in which the interpretation is clear—and fortunately the B minor Invention is one of them.
The trills in this theme:
... are played starting on the main note. It's possible to cite a technical explanation for starting these trills on the main note, namely that ugly fifths would otherwise ensue (in the beginning of measure 15 for instance). (This is indeed an example Badura-Skoda uses in his book.)
Note that the first three trills in this theme are thus pralltriller, while the last ornament (on the F-sharp in measure 3) is the opposite, a mordent.
A pralltriller consists of a main note, then its upper neighbor, and then the main note again.
A mordent is the opposite: the main note, then its lower neighbor, then the main note again.
The trills in measure 5 and the penultimate measure could, however, be played starting on the upper note.