Mailbag: “Resonating Reeds”

January 23, 2009

Dear Michael,

I’ve been wondering for some time: Since a reed’s pitch is determined by the length of the reed and not the resonator, is there a determined length-of-resonator ratio or rule or some such that will produce the best sound for its tone?

Morgan

 

Morgan,

The combination of an oscillating reed and an oscillating column of air (in the resonator) being coupled together is certainly a complex one. In the end, a full-length resonator determines the pitch while the reed is exciting the sound. In a short-length resonator, the control of the resonator is reduced. You can't have both - reed and resonator each completely in control. It is a mixture of the two, feeding each other and being connected together.
Finding the right length for both is the trick. A good reed voicer knows how to adjust the length of the resonator and the length (pitch) of the reed so that they work together for the best sound. Getting one reed pipe to sound well is tough enough, but getting all the others to sound that way is the real challenge. There is more than just the pitch of the reed and the length of the resonator to contend with. There is the scale (size) of all the parts and how they are connected that enters into this and they must all be factored into the process of getting things to sound properly. Knowing what to do with each part is very complex and requires many years of experience.
This has taken centuries to perfect. What reeds are today is much the result of many, MANY years of development and trial-and-error. We can experiment, but it usually is within the context of this long history of reeds. We know what works and what it takes to get a particular sound - getting there with each individual reed and rank is the test of the designer and voicer.
There are only a very, very few ranks in which the pitch of the reed is the all-controlling factor, and the short ‘holzregal’ is one. There really is no resonator to speak of since the sound comes right out of the end of the shallot.
The tuning is all done on the wire because there is no resonator to adjust. What we hear is the unmodified sound of the reed, and an example of what the resonator of a normal reed rank has to work with in creating the total sound of a reed/resonator combination.

–Charles Hendrickson, Hendrickson Organ Company, St. Peter, MN (APOBA Member)

 

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