Acoustics & Music Theory
why it sounds like that
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Notation hides things

Staff notation is a five-hundred-year-old compression. What it records beautifully and what it cannot record at all are both worth knowing.
CC♯DE♭EFF♯GA♭AB♭BCLydianIonianMixolydianDorianAeolianPhrygianLocrianbrightest at the top, darkest at the bottomeach row drops exactly one note by a semitone from the row above Scales and modes

The same seven, started later

A mode is not a new scale. It is the same seven notes with a different one treated as home, and the entire change in character comes from reassigning which degree the semitones fall next to.

 12345678x..x..x.3 onsets in 8 stepsthe polygon is what stays the same when the rhythm is rotated Rhythm and metre

Rhythm is a circle, and the bar line is a choice

Draw a rhythm as a line and it looks like a sequence of decisions. Draw it as a cycle and the same pattern turns out to be shared across continents, differing only in where somebody decided to start counting.

 1pureone partial, nothing else12345678stringall partials, falling12345678clarineteven partials nearly absent123456789bellodd partials onlyamplitude Timbre and acoustics

The ear hears the list, not the shape

Two sounds with the same partials and different phases have completely different waveforms and sound identical. What the ear extracts is a list of frequencies and strengths, and everything else is discarded.

 00.511.5200.20.40.60.81secondsamplitudeplucked — no sustainbowedstruck — no sustainkey released Timbre and acoustics

The shape of a note, which is most of what an instrument is

Cut the first fifty milliseconds off a recorded piano and listeners stop calling it a piano. The attack carries more identity than the steady tone it leads into, and it is the part every spectrum plot leaves out.

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