Musicians are often compared to athletes, but we usually don't have the numbers to do the analysis. On Friday's Performance Today, we'll quantify some speed: 72 notes played on a clarinet in seven seconds. That averages more than 10 notes per second. And in case you thought this is all sprint and no endurance, that pace continues for an entire page of music. Tune in for Carl Maria von Weber's lightning fast Clarinet Quintet with clarinetist David Shifrin giving Usain Bolt a run for his money.