[Harp-L] New Tool and Method for Improving Harmonica Reed Response

Laurent Vigouroux laurent.vigouroux@xxxxx
Wed Jan 16 10:34:30 EST 2019


Hello Vern and all

First thanks for this very interesting discussion.
A few comments from an "experienced amateur" much interested in diatonic harmonica, physics and scientific proof.

>From my point of view, the diatonic harp does have lots of strange behaviors, which are probably not easy to explain with physics. Not everything can be accurately modelized. The interactions between the opening and the closing reeds are really complex and very small changes (I really mean very small changes) can dramatically change the instrument response to bending and overblowing.

You're focusing on the "amount" of air leak in the chamber, but it could be that a small leaking from the bottom of the concerned reed produces a real difference (despite the fact that a much more amount of air is passing through the opposite reed) because there is more in the game than the  "amount" of air leak in the chamber. 

For example, on another subject,  squeezing of overdraws IS fixed by adding nail polish on the bottom sides of the reed (similar but slightly different from Brendan's solution). What are the physics that explain that? I don't really know. I've been told the squealing is due to torsional vibration and I guess "gluing" the bottom of the reed prevents that, but I'm not really sure. 

There is another way of dealing with this problem: adding a small square of turbotape in the middle of the reed. 
These two solutions most probably rely on different physics, and both work.

In my opinion, a scientist looks for explanations but also knows that the model of the moment can be wrong and repetitive experiences that lead to the same result oblige to admit there is something else happening than what is guessed at the moment. 

While the subject of the impact of comb material on the sound is very difficult to deal with, both in terms of experience process and because the impact is not that important (if any), the fact that a customized diatonic harp respond far better than a stock harp is very easy to demonstrate: have a stock Marine Band and a customized Marine Band, blow in them and voilà. It is that much noticeable. Brendan is totally right on this one. I've done that, and I can blindly switch harps and differentiate them any time. Anybody can. I don't really understand why you refute this.

Now, it is not easy to define precisely the impact of each type of modification (embossing, arching, nail polishing, adjusting the reed in the chamber, etc ...) on the playability, and even more difficult I think to understand the physics behind it. This is the craftmanship of technician. But the overall result is clear and this is what matters to musicians.

My two cents __

Laurent
www.planetharmonica.com



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