A long day in Palo Alto yesterday left me with little energy for the Master Class that Menahem Pressler gave last night at the San Francisco Conservatory of Music, but I could not resist giving the event the best try I could muster. That effort sustained me through little more than the first performance, which was of the first movement of Joseph Haydn's A flat major piano trio (Hoboken XV/14); but there was much to be gained from this experience, most of which had to do with Pressler emphasizing the need for a light touch at the piano to keep the instrument from dominating the violin and cello. This is a problem which I have discussed in the past, which is the tendency of any chamber music for piano and strings to sound like a "concerto for piano and very small orchestra." As Pressler observed, Haydn complicates this situation with a piano part that has about 75% of the notes (leading to the joke, which only a pianist would dare tell, that this would justify the pianist getting 75% of the fee); and this set me to thinking about just what it was that Haydn had in mind in conceiving of such a piano trio in the first place.
It is clear that Haydn was not thinking in terms of a concerto form; but it might not be too far-fetched to assume that he was thinking of a piano sonata which happened to have two obbligato parts for a violin and a cello. What would the role of those parts be that would make them so "obligatory?" My hypothesis is that, if we consider how closely those parts follow the voices in the piano part, they serve to endow the very sound of those voices with an instrumental "coloration" that the piano cannot provide. This seemed to be the sort of goal Pressler was trying to achieve by getting the pianist to play softer and the violinist to play louder, particularly in one passage in which the violin had to parallel a rather delicate embellishing passage in the piano part. (I found it interesting, by the way, that Pressler never addressed the cellist in this session, even though my own feeling was that the cello is also primarily there for a different shade of that "coloration.")
Unfortunately, this approach raises another problem, which is one of my personal favorites. This problem involves the difference between balancing contemporary instruments and those which are "period" instruments appropriate to Haydn's time. This particular trio is dated 1790, which puts it between Wolfgang Amadeus Mozart's K. 537 ("Coronation") piano concerto and his final (K. 595) B flat major concerto. Thus, one may assume that Haydn would have had in mind the sonority of a fortepiano similar to the one that Philip Bolt built based on one of Mozart's own instruments (which Malcolm Bilson has used for many of his concerts and recordings); and the strings would likewise have the sonorities of the instruments of that same time (such as those which the English Baroque Soloists used in accompanying the Bilson recordings of the Mozart "concerto canon"). This would mean a fortepiano with a far more rapid decay time that would be far easier to balance with a weaker violin and cello, both of which would have "softer" timbres, as well as overall amplitude. In other words, if Haydn's was going for particular effects of instrumental coloration in this particular trio, then this may be one of those compositions that is far better served by period instruments and may even be too frustratingly challenging to performers of more modern instruments. I make this claim knowing full well that Pressler and his Beaux Arts Trio had a great love of the Haydn trio repertoire; but this may be one of those cases where my interest in what I have called "accountability to the music itself" has more to do with sonority than with any logical or grammatical properties of the notated score.