I have two walton d’s that I removed the heads and filled the cavity Under the air ramp. For the experiment I put one head away and tried the same one on each tone tube. Then I polished the inside of one tone tube with brasso and the other I roughed it with emery paper on a stick. Played each tube with the same head. Nothing changed and they both sounded the same.
Mr. Tipple has had success using CPVC tubing for his flutes that have a “dimpled” bore…I wonder if this would help on a whistle. Based on your experimental resulsts, maybe not.
-Brett
In airflow theory there is what is called the “Boundary Layer”, a thin layer of air that isolates the surface from the main flow of air.
Those who make Model rockets have even experimented with ‘rough’ vs. ‘smooth’ paints and found the the ‘rough’ paints actually flew slightly higher. The dimples on a golf ball take adavntage of creating a heavler boundary layer that makes the ball sail through the air better.
What kill airflow in whistle bores is not the roughness of the bore, it’s sharp edges. Air has a certain viscosity and when pours over a sharp edge, it will converge inward. When you pour water out of a glass, there is arc formed by the fluid properties of water. Air too has fluid properties. Of course air is compressible and water is not.
If you make a copper whistle and cut the tonebody (lower portion of whistle below tuning slide) with a pipe cutter, it will make a sharp ring on the end. Then try cutting one with a bandsaw and file down the edges. Notice that the whistle cut by the pipe cutter with untreated edge will be significantly softer or seemingly robbed of it’s voice in comparison with the other whistle.
Very interesting… thanks
Very interesting. I have thought about this for a while but never got around to trying it. I have noticed that my Waltons Mellow D sounds a little rough if it gets “dirty” in the bore. Usually this is actually moisture plus dust. A quick swab cleans up the sound. My wife has even told me to swab out the whistle its starting to sound harsh.
I never thought about boundary layer effects on the bore. And I spent my career in submarine controls and acoustics. The speed of a body of rotation passing though a fluid is affected by the roughness of the surface and the affect is not intuitive. A rippled surface can be faster especially if it is a dynamic ripple. A fluid passing through a tube would be very similar.
Ron
Reyburn puts little bumps and protrutions in the bore of his whistles to fine tune the playability and sound of his whistles, at least some of them.
Yes Ron it is mostly moisture and dust that needs to be removed every so often. I think if it is left long enough there is some corosion that starts
also. It becomes sort of an internal microscopic carpet that deadens the tone. Pehaps when some pepole first start playing an instrument and are not aware of this they become discoraged in their regression of playing.
In my experiment I used 220 grit emery paper, maybe today I will try a more coarse grade.
A dimmpled surface and one prepared with rotating emery paper in a tube are almost entirely differant. I don’t know if the dimpples in Mr Tipples flutes are protuding or if they recede. But if Tipple and Reyburn are useing either they have tested and found benifit.
If I use a more coarse emery paper that will in effect create very small sharp edges as Bingham spoke of but they will be very small and more consistent to each other.
mmmm. I kind of agree, but not with the ‘robbed’ bit.
I make copper whistles with a sharp filed blade and I also make them with a blade formed by a tube cutter, similar to the way that O’Brien makes his. My sharp bladed whisles have a much sharper voice than the clearer, mellower voice of the tube-cut ones but I would hesitate to say that anything was robbed. The each sound different but neither is lacking anything. The beauty is in the ear of the beholder so to speak.
Jetboy.
AKA Simon
Weston Whistles UK
I’m not talking about the blade on the fipple window.
I’m referring to a section of the body tube.
If you join two pieces of the body tube together and pieces had been cut with a tubing cutter cause the metal to flare inwards so that ring like protrusion is present in the bore, it will greatly reduce the amount of sound present.
Effective area is reduced and reduces the amount of volumetric flow throught that section. That’s not necessarily bad, a quieter whistle is sometimes desired for practice purposes.
In regards to the sharpness of the blade. The parameters of the flue, window, blade position all interact with each other. There is no one best fipple geometery arrangement - there are several. And then, what’s considered perfect, some whistleplayers like flute-like sound and other more reedy like sound.
I noticed one time that a whistle body freshly dipped in water has very sweet tone to it.
If the end of a tone tube is trimed with a tubing cutter to bring the note up to a certian pitch, and the ring is not cleared it will mute the sound not destory it. It becomes destoryed if to much beval is cut on the end of the wind ramp or to much is cut off the leading edge of the blade.[/quote]
The other day I used a 600 very smooth emery paper to rough the boar and today I used a 220 more course. Then played each tube with the same head and still no change. I also tried a tube coated with olive oil inside and no tone change. But faster tunes seemed more easy due to oil on my fingers making a better seal. The oil on fingers may not be for everyone due to each haveing different texture of skin. But it might be interesting if there is some one that plays at warp speed and see if the small amount of oil on the fingers makes the notes pop quicker. And get to warp speed plus.
Olive oil in the whistle - I guess you call that an ‘anointed whistle’.
Arthur Benade wrote a document on bore of woodwinds, I retrieved this document from his widow. The porousity of the material that the bore made was more important factor than the roughness. Of with metal, this is not a problem - but on wood whistles, different story.
In reference to the protrusion in the body tube, think more about the section where the tuning joint is located. A ring-like protrusion can reduce the area flow by 50 to 80 percent of the original area.