by Scott Miller » Wed Dec 09, 2009 10:17 pm
When you hit certain notes, your head is vibrating at the same frequency as the refresh rate of your monitor - your head is acting like the strobe on a strobe light. Same thing explains why on old movies you'll see wagon wheels look like they're spinning backwards or if you use a timing light on a car engine, where you can "freeze" the timing pulley while the engine is running.
I think it's mostly noticeable for low brass players - I used to play around with the effect when I'd practice. Try staring at a digital alarm clock and playing different notes - when you see the numbers start to wobble, adjust your pitch up or down, you can get the numbers to look like they are skewed in place up or down on the face of the clock. Staring at area fans sometimes work as well.
On a side note (pardon the pun...) - in the US, the frequency of alternating current is 60Hz, a Bb (at A=440Hz), is 58.27Hz, and a B is 61.74Hz. We would have to kick out the cleaning crew vacuuming the auditorium in college when we would practice before concerts - the hum of the vacuum was pulling the tuning of the entire band sharp, as we would unconsciously tune to the vacuum.
And car horns honk in the key of F.