I understand from my music theory class that for reed and brass instruments, the "primary oscillator" is the modulation of an airstream. Comparatively, for wood winds, the "primary oscillator" is the air column.

I also understand that "oscillatIon" is a repeating waveform with a f0 and peak amplitude.

Fine, but what is a "primary oscillator" that is common to reed, brass, and woodwinds in the most generic sense of the word?


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    An oscillator is not a waveform. An oscillator generates a waveform. Feb 27, 2016 at 20:47
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    I think your terminology is a bit confused. In any musical instrument that produces a definite pitch, you have (1) something that oscillates, and (2) something that supplies energy to make it oscillate. For reed, brass, and wind instrument, the main thing that oscillates is the air inside the instrument. (The reed itself also oscillates.) The thing that supplies the energy is either the player's breath, or a mechanical system in instruments like bagpipes and pipe organs.
    – user19146
    Feb 28, 2016 at 6:26
  • Thanks! This is probably a naive question since I'm no physicist, but why is it necessary for instruments that produce a definite pitch to have an oscillator? Is there not some other mechanism through which pitch can be produced?
    – Teusz
    Feb 28, 2016 at 9:35

1 Answer 1


The common factor in all wind instruments is that sound is produced from a vibrating column of air, set into oscillation by a player's breath. But the air column isn't the "oscillator", it's the thing that is made to oscillate. So I think your theory class has got it a bit wrong! There are three ways in which a player may be the "oscillator". In a brass instrument he "buzzes" his lips into the mouthpiece. In a reed instrument the reed(s) take over the function of the lips. In a flute it's rather different, oscillation is the result of an airstream splitting in two when it hits an edge. So three different ways of being an oscillator, all with the result of getting an air column vibrating, ready to be shaped by the rest of the instrument. The flute family produce a waveform reasonably like the classic sine-wave picture, with an easily discernable frequency and amplitude. Brass and woodwind have much more complex waveforms. And a large part of the sound's characteristic, for all of them, is defined by the attack, where the waveform looks a LOT less tidy. As so often in musical topics I think you'll be better off learning how individual instruments do work, rather than searching for a Unified Theory. Maybe your teachers are simply looking for you to say "wind instruments work by the player setting an enclosed air column into vibration".

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