Tag Archives: spectral analysis

Partial understanding

Spectral analysis: no, not something from a Ghostbusters’ film, but a computer gizmo used by composers from the late(ish) twentieth century onwards.

Every pitch we hear normally comes with its own entourage of other ghostly sounds variously called partials, overtones or harmonics. It’s mainly the predominance of a particular gang of these (let’s stick with) partials that give any instrument its distinctive sound quality or timbre — how we tell a oboe from a flute from a violin; and kind of explains why some of the above mentioned composers describe themselves as ‘timbral’ rather than ‘spectral’ composers (don’t ask!!).

Here, for instance, on my rather grotty sine wave generator, are the first 16 partials of the note A – there are a lot more, stretching out way beyond human audibility.

 

Dubious? Iffy?? Ouch!??? All will become clear (eventually).

Anyway, the point of this exercise is to demonstrate that, in part, Western harmony springs from the ‘natural’ world of acoustics – look at partials 4, 5 and 6 and what do you have? The major triad! There is, however, a minor difficulty with this theory…

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