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Celebrating the pipe organ, the King of Instruments |
Mailbag: “Where does the sound come from?”
December 18, 2006
Dear Michael,
Many kudos to you for the Pipedreams program, it never ceases to be wonderful. OK, it’s my understanding that there are two types of pipes in a pipe organ (based on their construction). Flue pipes, and reed pipes. The flue pipes, I am told look somewhat like whistles, the reed pipes can look like almost anything. On to the question: I believe that the sound from a reed pipe originates at the vibrating reed (or shallot) itself, but is heard by the listener emanating from the end of the resonator. Is this correct? Does the sound come to the listener via the resonator (or shall I say out the end of the pipe?). On the other hand, since flue pipes seem to always have a visible mouth on them, is this where the sound originates on a flue pipe –at the mouth? And, in conjunction with that question, does the listener hear the sound from a flue pipe via sound waves which come to the listener directly from the pipe mouth? Or, does the listener hear the sound coming to him/her from out of the very top of the pipe (at the opposite end from the mouth)? I hope these questions are not too convulted for an answer, thanks very much.
Dave Davis
Mission, KS
Dear Dave,
You can check out some of your theories by clicking on “see image” on our “How It Works” page:
As for reed pipes, they function like a single-reed orchestral instrument (clarinet, saxophone), though the ‘reed’ is brass rather than plant material. The shallot, by the way, is like the mouthpiece, against which the reed/tongue vibrates.
And, just as a saxophone sounds different from a clarinet (or a bass clarinet) depending on the side, shape, and general physical characteristic of the ‘instrument’, organ reed stops differ in their tone because of the many different sizes and shapes of their resonators. The sound comes from resonator. Remove the resonator from the bood (in which the shallot and reed are located) and you get a very strange tone indeed…like playing a bassoon double-reed without the bassoon.
The sound of flue pipes also is ‘qualified’ by the length and general physical dimension (wide or thin, tubular or tapered) of the overall pipe. The ‘mouth’ works like the mouthpiece on a flute…that is where the air is set into vibration as it comes from the toe through the little slit at the languid (like an emboucher) and then ‘split’ on the upper lip of the pipe mouth. The relationship of those parts impacts the quality of speech (fast, slow, articulate or smooth), but the shape/length of the pipe has impact on the tone color and pitch.
JMB
