A “brass quintet” consists of two trumpets, French horn, trombone, and tuba. I attended a concert by a brass quintet the other day, and I was struck by a big difference, visually, between a brass quintet concert and, say, a string quartet concert. When you watch a string quartet, you see lots of movement – arms, hands, fingers, instruments. But at a brass quintet concert the only thing you see moving much at all is the slide of the trombone. And the reason is that most of what brass players do is done with the lips, and it’s invisible to us.