Tunborough wrote: ↑Sun Mar 26, 2023 8:02 am
The comparison I was making was not windway relative to blade (which is an important consideration for voicing in its own right), but windway and blade relative to the centre-line of the tube. Looking up the head of a Generation, from the open end toward the windway, I see a fairly sizable circle segment above the bottom of the blade and the windway exit.
OK, starting there, I've tried various approaches to get a good view. The Zoom microscope doesn't do much as the ring of LEDs that are used for illumination are shaded by the socket walls. Ditto the Maggy Lamp, for the same reason. Best viewing seems to be using a strong bench lamp.
Looking into the Old Gen, I see first the reduction from tube outside diameter (about 12.7mm) to tube inside diameter (about 11.5mm) that stops the tube from inserting too far. Excepting that it's D-shaped, not a full circle concentric with the socket - the spine of the D being a platform underneath the ramp. I can get a Telescoping T-gauge into that area. It suggests a horizontal width of 11.45mm, but a vertical width (if we take the window side of the head as "up") reduces to about 10.4mm. So the platform drops about 1mm. If I then push further in so I'm seeing the T-gauge tips about to enter the window, the vertical diameter drops a little to around 10.2, but the horizontal diameter drops a little to, to about 11.35. These are probably not acoustically significant details, being more about some tapering to be able to get the head out of the mold!
And beyond that, I can see the end of the windway and the cavity below it. But finding a way to measure how it relates to the platform or circle isn't easy. I took a 9.5mm brass rod and faced it off cleanly, offered that up the head socket until it reached the end of the windway. I could rock the head until I was confident that the platform was sitting on the rod. At that point the outer circumference of the rod came up to the bottom of the windway exit.
And yet, when I look down the windway, I can see some through as well as mostly ramp. But it's possible that the windway isn't parallel to the rest of the whistle, isn't it! So, while inconclusive at this point, there may be some scope there for measurement systems.
The blade hangs lower into the bore than it does on a Feadog Mk 1.
Agreed. Using the same approach on the Feadog Mk 1, the horizontal head bore after the socket is 11.9mm, while the vertical is about the same. And I couldn't get a good sense of a platform to try the brass rod test. I just got the sense that the head was rocking on the bottom of the blade.
A more recent Generation looks the same as Old Gen, but when I get to the brass rod test, I reckon about 5mm width of the circumference of the end of the rod passes above the floor of the windway. That's consistent with seeing more "through" when looking from the beak. But again, perhaps we're getting more into voicing here than what you're looking for.
The Mellow D shows a small platform, but again I have difficulty assessing its relationship with the windway exit.
And the Killarney as I mentioned previously is no mystery. All you see up there is the perfect circle that forms the bottom of the tube socket. The stopper and bottom of the ramp are all at that reduced diameter.
I'm sure there's at least one academic paper in this, if only we had an academic to take notice.
Hmmm, does this take us back to my University of Limerick Physics Department quip? Anyone aware of anyone working in this field these days?