Re: Why does the ceiling fan change how my flute sounds?

The Question:
I came home the other day after walking in some obscene temperatures to
practice flute in my living room. I turned the ceiling fan on high because
of the heat, and stood on a chair so I could see my music on top of the
piano.  When I was playing, I noticed this shaking sound on the notes; it
was like involuntary vibrato that I had nothing to do with, so I concluded
it was because of the fan. It was especially noticeable on high notes.  Why
did the ceiling fan change the sound so much? Why was it worse on higher notes?

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Great question!  

As the blades of the fan pass overhead, they echo the sound of the flute. 
When the blade is absent, the sound echoes from the ceiling, and is not as
loud.  So the loudness (volume, amplitude) of the sound varies many times
per second as a blade passes by.  That’s essentially amplitude-based vibrato.

Stringed instruments use frequency- (pitch-) based vibrato.  The violinist
wiggles his finger towards and away from the far end of the instrument,
changing the effective length of the string.

I think the reason you encountered a more noticeable effect at higher
pitches is that there’s more energy in high frequency notes than in lower ones.


Best wishes,

~Aaron