Here’s one for all the whistlesmiths out there. It’s probably a dumb question, but one that nags me whenever I pick up my whistle. I understand the concept of a longer/wider tube producing a lower tone. However, what I don’t understand is how the size of the holes affects things. Looking at my Water Weasel, holes are drilled in roughly 3 different diameters. Obviously, Glenn uses different sizes for a reason. But, I don’t understand the science behind what this does for the tone. What gives? Thanks.
It is to make the placement of the holes comfortable for the human hand. A smaller hole makes a flatter note, like half-holing. If the fourth hole wasn’t small, it would have to be very close to the fifth one, because F sharp is only a semitone below G. So making it smaller compensates for having it further up from the fifth hole.
Take for example, a small 1/4" hole plays a certain note. A whistle maker can move that hole downwards a certain distance but as the hole move downward, the diameter has to be enlarged so that it can play the same note. It can only be move so far though, after certain distance the hole either become too big to cover or the diameter of the hole reaches the same as the bore diameter (it doesn’t really matter after it exceeds that size)
Something else happens though.
The whistle with the larger hole will have a higher ‘cutoff frequency’ what this means is that the tone produced will have more high frequency components in it and sound rich. The smaller hole will have less of these components and might even sound weak.
The length of the tube is varied by opening holes, if the tube fills with air and drains back out 440 times per second, you hear an ‘A’.
The length of the tube changes the fill time, if you make the tube longer and it takes longer to fill and happens to be say 392 times a second, now you’re playing a ‘G’. The size of the hole and it’s position allows the tube to fill and drain at different rates.
Also, the size of the hole will affect the amount of pressure peak that is occuring, this will affect the volume and quality of the tone.
Airy sound that varies on some whistle is caused “mainly” by the way the fipple is designed.
Good explanations above.
Just to add that the C# hole is the most tricky to get right, this is because not only must it play C# in tune but also play the cross-fingered Cnat correctly. For a given Cnat fingering this means that the size of the C# hole (the smaller the hole the greater the flattening effect of cross-fingering and vica-versa) is fixed, so the position has to be dead on.
I think most makers achieve this through a process of successive approximation. Because holes get sharper as there centre moves up and as there diameter gets larger removing material from the top side of the hole will sharpen a note with a relatively small diameter change as compared to the bottom part which for the same amount of sharpening will lead to a greater increase in hole size.
TTFN
John S
Since we are into technical questions (though I’m sure it is covered somewhere else and I have missed it) what is the musical difference between conical and cylindrical bore? Volume, Back pressure? Always wondered. Thanks, Danny.
Thanks for the responses. I’m beginning to understand. I’d imagine that a whistle maker must have to go through a lot of prototypes to get the holes in the right spot with the correct diameter.
Despite what these other guys are telling you, the different hole sizes and placements are completely arbitrary, we’re actually just messing with your head. 
Loren
I always suspected that there was a vast chipple conspiracy to keep that fact a secret. Luckily, I was able to unmask the plot by using special goggles to read the encrypted message printed on a McDonald’s Happy Meal. I bet you got the idea from watching the movie “National Treasure”.
Actually we pass our secret code by cutting out the first sentence on page 13 of the local newspaper and sliding the strip into a Clark High-D and the letters that show through the toneholes is encryption key.