The last movement of Samuel Barber’s Violin Concerto portrays nervous anxiety, even panic. The title of the movement, “presto in moto perpetuo” translates “very fast perpetual motion.” It’s like riding a wild roller coaster with no hope of getting off. The violinist literally plays fast sixteenth notes (4 notes per beat, 170 beats per minute (BPM), that’s like 10 notes per second) the whole movement. Four minutes straight. In order to achieve this, the performer must practice the sections over and over again at a slow tempo and work his way up to 170 BPM. This can take dozens, even hundreds of hours to perfect the way the violinist in this clip has.
The fast-moving action in this piece reminds me of a great chase scene out of a movie. Actually, the music sounds similar to the soundtrack from one of the recent Harry Potter movies. The feel is chaotic, frantic, dissonant, high, fast and loud. You can even hear the horns in this clip sounding the hunt, just as they did for centuries in Western Europe. This is the last 30 seconds at the climax:
How does Barber illicit such a visceral reaction? The fast, perpetually moving notes is one effect, but so is the near atonality of the violin part. Atonality is just as it sounds: an absence of tonality. This means the violin isn’t really sticking to the 8-note scale of a key. Instead, it is playing any one of a 12-note scale at any time. This confuses our ears because we don’t know where the music is headed. Music is the most dissonant when it is atonal. The notes are not random by any means, and if the music were slower, we could probably discern a recognizable, though dissonant melody. But in this case, you won’t be humming this piece later today. It is the feel of chaos and frantic anxiety that sticks with you. But hopefully the excitement of the chase does, too!