That mysterious number, by the way, comes from a catalogue of all Schubert's works compiled by Otto Deutsch and first published in 1951. It was very needed because Schubert wrote just shy of a thousand pieces of music and some way of uniquely identifying them was urgently needed. One of my petty beefs with the local chamber music society is that when they promote a concert they tend to do so by announcing that the artists will play "Haydn's Quartet in C major" as if it was the only one he wrote. Haydn wrote at least a dozen quartets in C major and my urge to attend the concert varies widely depending on which one they are playing! But enough of that, as we can see from the Deutsch number, assigned according to the chronological order of composition, this sonata is a late one, written in the last few months of his short life. Wikipedia has a good article on the last three Schubert piano sonatas.
The Piano Sonata in B flat, D. 960, is in the usual four movements. The multi-movement format is one that is common in classical music and almost unheard of in more popular genres. We also find it in a the music of a number of non-Western cultures such as the Andalusian suites played by ensembles from Morocco to Egypt. We find the idea of suites combining separate pieces in different tempos in the music of Thailand and other places in Asia. The piano sonata, which is a form developed in the later 18th century, normally has four contrasting movements played with a short pause between. The first movement is usually in sonata form, which is often called "sonata-allegro" form or "first movement" form because most first movements are allegro (meaning quick and lively).
The rest of a typical piano sonata (which shares this basic structure with the other big genres such as the symphony and the string quartet) usually consists of a slow movement, a minuet or scherzo, and a quick last movement. Today I just want to talk about the first movement which, in this particular sonata, runs over twenty minutes in length. How can you construct a piece of music that long? This is the question that the composer is confronted with. Remember that the basic issue of music composition is the balance between repetition and contrast. Some kinds of music avoid or sidestep this issue in various ways, but most of the core repertoire deals with it directly.
Schubert's first movement is longer than most because he has developed a structure that is a bit more complex than most, even Beethoven. The challenge to the listener is that the structure is built largely through key relationships--harmony. Let me talk about that a bit. Harmony is perhaps the most mysterious of the three fundamental qualities of music: melody, rhythm, harmony. It might be interesting to note that all three of these words come from ancient Greek (melos, rhythmos, harmoniai)! The Greeks of the 5th and 4th centuries BC developed a complex system of music theory based on the acoustic discoveries of Pythagoras. Much, much later, the Middle Ages in Europe developed quite a different system, but kept using the same terms.
Harmony and melody are both about pitch, while rhythm is about pulse. Melody is the rising and falling tune that is perhaps the most salient aspect of a piece of music. Harmony is more in the background. In one sense, harmony is the chords that accompany a melody, but in the larger sense, it is the overall relationship between these chords over the whole movement. To understand this, you have to have an idea what a "key" is. When we say a piece is in the key of C, we mean that the melody and harmony are chosen from the notes available in C: CDEFGAB. There are a lot of pieces that don't go much beyond that. The most important chords are those on C, F and G, the "tonic" or home key note, the note a fourth above and the one a fifth above. Hundreds of songs use just these chords. For variety a songwriter might toss in a bit using A minor. Songs have interesting lyrics about stuff like love and are usually just a couple of minutes long. But when you are working with a timespan ten times as long, this is going to get boring! Of course, the whole minimal music thing started with a long piece just using these notes by Terry Riley called, obviously, "In C."
Suppose you are a guitar player and you have a friend who is a singer and she wants to do a song with you but C is just not the right key for her voice? This brings us to the fascinating concept of transposition. You don't want her to wander off to a different guitar player, so you transpose the chords into a different key. Guitarists have a neat way of doing this using a capo which is a little bar that fits across the fingerboard, shortening the lengths of the strings and therefore moving the pitch (the frequency vibration) higher. Here is what it looks like:
As you can see, if you play exactly the same chords with the capo on the second fret, they will be higher in pitch: a major second higher. If you are playing a C chord, it will now be a D chord. Keeping everything the same, the notes now available will be DEF#GABC#. Those little signs indicate that the F and the C are sharped, or one semi-tone higher. This preserves the relationship between the notes when we start in a different place--in this case, two frets higher.
The Piano Sonata, D. 960, is in the key of B flat, which is two frets below C on the guitar. I am just referencing the guitar because we can see these relationships on the fingerboard. Alas, the capo just goes up, not down, so the poor guitar player, if he wants to do the song in B flat, has to transpose the chords. C is now B flat, which means that F is now E flat (two frets below) and G is now F (two frets below). If you have the basic idea, I will leave the guitar now and go back to the piano. Transposition is easier on the piano, though less visual than on the guitar.
There are quite a few different keys available as you can make any note the home of a key, not just the basic notes (the white ones on the piano), but all the ones in between (the black notes on the piano). You can play in the key of G flat just as you can in the key of C. This is just what Schubert hints at in the opening of the piano sonata:
|Click to enlarge|
I recently watched a movie that used this very piece in a fascinating way. The movie is Ex Machina, a well-done film about artificial intelligence. Very near the beginning of the film a young man pays a visit to his billionaire tech boss at his retreat in Norway. A computer gives him access to the house and as he comes into the living room, we hear the opening of this sonata playing on the sound system. That ominous trill is a brilliant way of foreshadowing what will happen later in the film, just as it foreshadows what will happen in the sonata.
I have to introduce one more concept: those black keys we see between the white ones on the piano keyboard:
These notes, as you can see, have two names. You can call the black key between A and B either A# or B flat according to your needs. That note can be spelled in two different ways. It goes even further. The B note can be spelled C flat, the E note, F flat and so on. We even have double sharps and double flats, but I can see you folks in the back dozing off, so I will spare you.
Yes, those quirky notes are also used. Looking back at the excerpt from the sonata, if you count down those ledger lines below the bass clef (just look up any of these terms on Wikipedia as necessary) you will see that the first teeny-tiny note is an E flat, followed by an F flat and a G flat. What makes this so jarring is that the most important structural note in B flat, after the home note itself, is F, the dominant. F flat is the note just below F and G flat the one just above, so the trill is really jarring.
How Schubert uses this is first of all to foreshadow the middle part of this opening theme which goes to the key of G flat:
But it goes even further. The middle part of the first theme itself foreshadows the second theme which is in the key of F# minor:
If you look back at that image of the keyboard, you will notice that the other name for G flat is F#! Oh, and yes, you can have a major key or a minor key on every note.
Now I have the feeling that circuit breakers are about to blow, so I will stop here. You need to listen to the movement now, several times if possible. Each time you listen, try and keep track of that low trill in the bass. It can be a guide for you through the movement. The pianist is Alfred Brendel: