Beat of a Different Drummer?

In my dissertation research I’m turning toward drum machines. It’s a natural extension of my ’80s sound inquiries: if the Yamaha DX7 was so important to the ’80s sound, drum machines like the LinnDrum and the Roland TR-808 were at least equally important.

Analyzing the timbre of drum machines using my existing apparatus has revealed how biased toward pitched phenomena theories of timbre really are. For example, so many theories of timbre are completely preoccupied with overtones/partials and their relative loudness. (For more info on spectrogram analysis, check out the first half of this blog post.)

This spectrogram is of a harmonica synth playing a melody. Time is on the x-axis in seconds. Pitch is on the y-axis in Hertz (higher Hz = higher pitch). The bottom line of this spectrogram, at around 500 Hz, is the fundamental pitch. Colloquially we just call this “the pitch.” The parallel lines running above the fundamental are the partials of this sound. You don’t hear them as separate notes, but instead you hear a change in timbre.

But for many percussion instruments, drums and cymbals and such, you won’t see any partials like that at all. Even drums that are pitched don’t really have partials running in multiple parallel lines above it.

all sounds mono.png — These are samples from a Roland TR-808: bass drum, low tom, mid tom, high tom, snare, closed hi-hat, open hi-hat, clave, and handclaps. Notice how these are all just thick bars of sound, not at all like the parallel strands in the above example.

So it does us no good at all to talk about partials, how those partials compare to the ideal natural harmonic series, whether there’s vibrato, etc. Yet, that’s the majority of the focus of spectrogram analyses.

Over the next few weeks I’m going to start finessing how we can talk about timbre in non-pitched percussion instruments. For now, back to the grind…