The air horns the spectators blow at races produce a curiously downbeat effect; they seem to drop in pitch in the second or so in which they sound. In the very first moment they're like a siren, brusque, alarming, but then the timbre emerges and it's a bit of a moan, and it trails into something like a baby's cry. You hear them the most when the race is over, on the victory lap, and they're saluting the winner of course, and all the drivers, in fact, jubilantly, but the chorus has a valedictory, melancholy quality. It's over and there's nowhere to go but home.