Author: Matt74
Date: 2020-11-10 22:25
Attachment: CF195089-B820-482B-AC4F-109D84AED395.png (211k)
I think what you are looking for is called “Vibrational model of single reeds.”
I found this page, which discusses clarinet reeds, but I didn’t see anything about the harmonic nodes of reeds. https://newt.phys.unsw.edu.au/jw/basics.html
This confirms that the reed changes frequency with the column. https://physerver.hamilton.edu/courses/Fall13/Phy175/ClassNotes/Reeds1.html
My guess is that reeds are very “dirty” harmonically, and do not have identifiable nodes, which is why they sound so bad without a resonator.
Here’s a paper about Ullieann pipe reeds. It says the reed does not have harmonic nodes when vibrating freely. http://www.tuftl.tufts.edu/musicengineering/research/uilleann_pipes/uilleann_reed.pdf
It says:
“Looking at the data we can see that the previously mentioned models do a poor job of predicting the motion of the reed. A similarity that does come to the forefront is that our reed is presumably not harmonic in its vibrating nature like all of the previously mentioned models. We can see however that the reed vibrates at harmonic frequencies. Indeed since the instrument in question has a conical bore with a pressure node at one end, and an anti-node at the other theory dictates the reed must vibrate at harmonic frequencies. If we trust the models and assume that the free vibration of the reed is not harmonic then we can say that the air column below the reed dominates the vibrational structure of the reed and forces it to vibrate at harmonic frequencies.”
***So what you really want to know is: “How does the reed vibrate in sympathy with any given partial or note of the clarinet.”***
The paper does confirm that some traditional adjustment practices are effective at producing the desired effects. Obviously, this would be different for single reeds, and single reeds MAY be more harmonic, because they beat against a mouthpiece, not another reed.
More stuff: https://www.semanticscholar.org/paper/Influence-of-strain-gauge-sensors-on-the-behavior-Chatziioannou-Hofmann/0f8f2f524e14edce58b134a1f83a9096bcca27ef
I found pictures there of saxophone reeds vibrating at different column nodes, attached. The description is:
“Figure 4: Decorrelated electronic speckle pattern interferograms of clarinet (left) and saxophone sensor reeds (right) oscillating at their first three resonance frequencies. At every mode the operating deflection shapes are shown from left to right corresponding to no sensor, one sensor and two sensors mounted on the reed. Nodal lines are represented by white regions and moving areas by correlation fringes.”
I think that since the frequency of the reed changes, that the precise “node” of the reed might move depending on how long the column is, but it’s a place to start.
- Matthew Simington
Post Edited (2020-11-10 22:33)
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The Clarinet BBoard
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