Just some thoughts.de Salier wrote:The main question is, do you make the windway narrower, do you raise the floor, or lower the roof, or a combination of the 3
In most whistle designs it is critical to get the geometry between the floor of the windway and the edge of the blade correct. It very much determines how well the whistle will speak.
So to restrict the windway to use less air you would generally want to lower the height of the windway by modifying the ceiling of the windway somehow. If you are familiar with the classic squashing of the top of the windway on Clarke originals you'll get the idea. How you perform the same trick on other whistles is up to you. In some cases you can merely restrict or redirect air flow at the top of the exit of the windway. But it's touchy business.
Narrowing the windway from side to side will reduce the air input but mostly it will result in lower volume. It does not usually change the geometry between the exit of the windway and the blade. There is one design where that is the exception. That is on whistles where the blade is formed by simply cutting the head pipe on an angle to form the edge. On those, narrowing the windway limits the airstream to the middle of the blade where that design is more-ish efficient and it avoids sending air to the edges where it mostly makes hissing noises. Fashioning a vee shaped channel might make the most sense in that case.
On some whistles that need to be "pushed" the airstream does not hit the blade so that it oscillates optimally (IMO). There are a lot of reasons that will vary depending on the design of the head. On those that may be wooden whistles with wood/cedar plugs they may share an issue common with many wooden recorders. The plug changes shape, usually swells a bit but could also have shrunk, and it needs to be re-shaped. The whistle gets stuffy and requires a lot of air velocity to do the job as the frequency of the notes increases. Bits of millimeters count in these cases.
The Overton/Goldie design is very specific, speaking of the "hard blowers". The OS Chieftains were similar IMO. They have a low windway height by design. The focus of the airstream hitting the blade is well aimed. It works very well, uses little air but requires comparatively more pressure at the mouthpiece than other whistles. Chances of overblowing a note on one of these is low. Some players appreciate that, while others may not.
Feadoggie