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My shaver is an almost perfect Bb, microwave is high A and my vacuum cleaner is a flat Ab. I have found my self using these as drones to practice intervals, and at other times to figure out what key the current song on the radio is played in.

So, am I the only one geeky enough to know the pitch of my household appliances?

For years guitarists have used the 60-Hz hum to tune their B strings before personal tuners were common and on occasion if a pitch pipe, piano, or tuning fork were not available. B is actually 61 Hz or so, so a guitarist would tune the B, then tune the G "dead," then tune the rest of the strings, then pull the B up a hair to "equal temperament" so the top E would not be flat.

When I was younger, anytime I would put something in the microwave, I would sing a bunch of intervals while I watched my popcorn pop.

I sometimes harmonize with the vaccuum. Unfortunately, at school one of our practice room has a buzz that's a flat B or sharp Bb. Incredibly annoying when I'm trying to work on long tones

Søren wrote:My shaver is an almost perfect Bb, microwave is high A and my vacuum cleaner is a flat Ab. I have found my self using these as drones to practice intervals, and at other times to figure out what key the current song on the radio is played in.

So, am I the only one geeky enough to know the pitch of my household appliances?

Equipment that have synchronous motors in Europe use the 50-Hz mains power to derive their speed. A typical synchronous motor will run on one of the harmonics of the mains frequency depending on how it is wound. 50 Hz is a low G that is 35 cents sharp.

Induction motors, such as those used in major appliances such as washers, dryers, and air-handling systems, slip from the harmonics of the mains frequency. So, their frequency is a bit lower with respect to those. An induction motor will be close to a harmonic of Bb in the U.S., where the mains frequency is 60 Hz (a low Bb is 58 Hz), but there must be something else happening on a 50-Hz system.

DC motors might turn at any speed. Shavers use a vibrator that wiggles a shaft in a solenoid coils back and forth with the mains frequency. Battery-power shavers, however, use a DC motor that drives an eccentric cam for wiggling the shaver head, and will run at a speed related to the voltage of the battery. Those can run at any frequency.

Rick "who has actually looked at FFT spectrum analysis of some appliances" Denney