Motorcycle Music

Next time you’re on the highway at 70 mph next to a roaring Harley, roll down your window and listen (but do not breathe!). I did this just the other day, and was struck by something strange about how the chopper sounded. The motorcycle’s “footsteps” were there, namely the sounds made by the bike’s impacts directly on the asphalt as it barreled over crevices, crags, and cracks. The motorcycle’s “banging gangly” sounds were also present–the sounds made by the bike’s parts interacting with one another, be they moving parts in the engine or body parts rattling due to engine or road vibrations. And the bike’s exhaust pipe also made its high‑frequency vroom (not quite analogous to a sound made by human movers). These motorcycle sounds I heard were characterized not only by their rhythm, but also by the suite of pitches among the rings of these physical interactions: the bike’s “chords.” These rhythm and chord sounds informed me of the motorcycle’s “state”: it is a motorcycle; it is a Harley; it is going over uneven ground; it is powerful and rugged; it needs a bath; and so on. Rhythm and beat (and the chords with which they seem inextricably linked), the topics of much of this chapter thus far, are all about the state of the mover–the nature of the mover’s gait, and the emotion or attitude expressed by that manner of moving about.

What, then, was so strange about the motorcycle sounds I heard while driving alongside? It was that the motorcycle’s overall pitch and loudness were constant . In most of my experiences with motorcycles, their pitch and loudness vary dynamically. This is because motorcycles are typically moving relative to me (I never ride them myself), and consequently they are undergoing changes in pitch due to the Doppler effect, and changes in loudness due to changing proximity. These pitch and loudness modulations give away the action , and that was what was missing: the motorcycle had attitude but no action.

Music gets its attitude from the rhythm and beat, but when music wants to tell a story about the mover in motion –the mover’s kinematics–music breaks out the pitch and becomes melodic, and twiddles with the volume and modulates the loudness. The rest of this chapter is about the ecological origins of melody and loudness. We will begin with melody, but before I begin to defend what I think musical melodic pitch means, we need to overcome a commonly held bias–encoded in the expressions “high” and “low notes”–that musical pitch equates with spatial position.