While I was reading the “Shocking Bore” thread,
Terry McGee wrote:
This statement abraded me as I read it! It seemed to me that relatively, a good Irish flute player would use a minimum amount of air to produce a large volume of sound, which would certainly be of an efficiency greater than 1%. So I sought to quantify the work applied (blowing into the embouchure) and the work produced (sound), to get an idea of the efficiency of the Irish flute and provide a relevant example.Some time back I asked Prof. Neville Fletcher why Cooktown Ironwood, which often doesn't take a high finish, seems always to make a very lively flute. He discounted the dimples on the golfball theory (which relies on breaking up laminar flow and the drag it creates), and suggested it might be due to less thermal loss to friction. About 1% of the pneumatic energy we put into our flutes comes out as sound, most of the rest goes to heating the flute (not to be confused with the actual heat of our breath heating the flute).
First off I’ll pose a question: Which of the following requires more work on your part?
1) Blowing through a drinking straw, moving a wooden pencil 20 centimeters across a table top in one second.
2) Playing your Irish flute in a relatively soft easy manner.
Personally I think blowing the pencil is harder.
* I assume the efficiency of blowing through the straw on the pencil is greater than 50%. This is based on my limited experience with pumps and turbines.
But according to the calculations, both of the above require approximately equal amounts of energy.
Well, having been decades since I last took a physics course and having jettisoned most of my old texts, I found on Wikipedia a relationship between sound and energy (1 dB = 20 micro Pascals). Now to put this conversion to use:
To get things started, let us assume the following:
a) Around the house I typically play at about 50 dB as measured by the “Auto Tuner” program. This is probably rather soft playing compared to most Irish flutist.
b) The weight of a typical wooden pencil is 5 grams.
Now the math, briefly:
A Pascal is typically used for pressure and is not the best unit of measurement for work. But, 1 Pascal is equal to the force of 1 Newton applied to an area of 1 square meter. This in turn equates to 1 kilogram per meter per second squared or the acceleration of an object 1 meter every second weighting 1-kilogram. Is this clear as mud?
Now if we factor these into the above equation we get:
50 dB = 0.001 Pascals, which is equal to the ability to move our wooden pencil 20 cm in 1 second.
50 x 0.00002 = (5/1000) x (20/100) = 0.001 <-- numbers
dB to Pa = (kg to g) x (m to cm) <-- units
Thus conclusively proving nothing, except that I believe the efficiency of an Irish flute with a good player is greater than 50%.
All the Best!
Jordan
) to relating the efficiency of the flute is missing. I need a simple machine and its relative efficiency to be able to compare it to playing the flute.
"It might be a bit better to tune to one of my fiddle's open strings, like A, rather than asking me for an F#." - Martin Milner
