Re: [Harp-L] A few thoughts on reeds, since we are muzing it seems.




On Aug 10, 2010, at 9:29 AM, Dr. Michael J. Marino, DC wrote:




 Since we already know that the frequency you get is a complex result
(tip width, length of reed, elasticity of the metal, density of the
metal) why not see if we can take it one set further and see if the
complex curved free reeds used in concertinas and accordions can be
applied to the smallest of the family the harmonica.

Some aspects can be used between the two instruments, but keep in mind the following:


1... A normal person at rest (sitting watching T.V.) is only taking 24 ml breaths (abt 1.5 cubic inches)
2... Walking around it's more like 80 ml (5 cu. in.)
3... Deliberate breaths are still only abt 275 ml (17 cu. in.)
4... It takes 500 ml to activate the cyllinder in a breathalyzer or the hall of mirrors in an intoxilyzer.
(a) Most people need 2 breaths (abt 30.5 cu. in.)
5... A small concertina puts out 900-950 ml in normal play (abt. 56 cu. in.)
6... A Cajun diatonic 1 or 2 row accordion puts out OVER 3 litres. ( abt 190 cu. in.)
7... Even a small accordion (say 27 keys) can open up to over 10 litres (abt 625-650 cu. in)
8... there are over 7.5 gallons in a cubic foot. A large accordion (say 41 key) can (played by a long armed person) put out well
OVER 9.5 gallons of air.
Pre conclusion? These can rely on Beau-COUP amounts of air.


Conclusion? The reeds in these instruments are geared to this law of physics, are usually spring steel (blued) or stainless in the slightly better models and bronze in the most expensive models. So this has to be taken into consideration.

As for the shapes. That's a different matter and certainly open for lots of experimentation. Accordion reeds are usually tapered. THAT is an additional expense. They are usually DOUBLE riveted. Another expense. The wind savers usually have a thin piece of wire on top of them to keep them flat. Another expense. The reeds are usually set in pairs on a common plate. There is an air release valve so that the reeds aren't over stressed.

Harmonica reeds HAVE to be (relatively) flimsy by comparison. Otherwise it would take a wooly mamoth to activate them.

Bear with me as
this is not just being a stick in the mud. The complex edge curve you
find in high quality concertinas and accordion instruments helps to
eliminate unwanted secondary harmonics that are not naturals of the
root frequency desired.

This is true.

Now if this was applied to the harmonica we could get a much truer and sweet note from the instrument as much of the noise would be eliminated.

Interesting and worth investigating. Accordions stay in tune because of their pressure relief valves. Harmonicas go out of tune (primarily) because they are played "As a VOICE", and any deviation from the normal air flow (bending..over blowing..slurring, etc.) risks knocking the reeds out of kilter through stress. Accordions cost thousands and thousands and are designed for a certain modicum of abuse.

Now comes the question of how to test and find if this makes a favorable sound or one that takes away from the qualities that area a harmonica. I am just beginning to look deeply into the math that goes with this and it can make you head spin.

Math? well that let's ME out. :)


smokey-joe & the cafe s


So anyone interested please
contact me as the outcome could be very interesting indeed.

Michael






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