Mailbag: “Helium?”

October 25, 2010

Dear Michael,

Your contribution to the world of organ music and instrument building should bring you the medal of congress. As a matter of curiosity what would happen if a pipe organ was powered by helium? Any ideas?

Jean

 

Jean,

According to my ‘resident expert’, Minnesota organ builder Charles Hendrickson:

The pitch of the sound from a pipe is determined by the speed of sound in the oscillating medium (air, Helium, etc.) and the length of the pipe resonator. Helium would have a very large effect in raising the pitch of any pipe.
The pitch of a pipe is related to the the time it takes a vibration to get from the mouth to the top and back down to the mouth. The speed of sound in air is about 1120 ft./sec. For Helium, it is about 3000 ft./sec. Thus the vibration in a pipe on Helium would be about 3 times the frequency of it on air.
These same parameters directly affect the way that pipes go up and down in pitch with changes in temperature, since there is a change in the speed of sound as the temperature changes. Faster velocity resulting from increasing temperature makes for higher pitch (organs go sharp when the temperature goes up, and go flat when the temperature drops). -CH

 

jmb

 

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