Tunborough wrote: ↑Tue Apr 04, 2023 7:28 pm
From those numbers and measurements on a Feadog here, I would have thought the tube was a hair longer, more like 245 to 245.5 mm from blade to open end. Is this a possibility?
No, measured more carefully it comes in at 243.6mm. Now, the Window Length is 5.32, I don't suppose I was guilty of tampering with the edge back in the day? We did desperate things back then. We had to!
We're seeing overlap (hysteresis) between the second and third regimes and third and fourth regimes, but not between the first and second. What's happening between 10.9 and 11.8 L/min?
Primal Chaos. Firstly you hear the higher regime starting to sneak in, then it gets warbly, and then the lower regime exits the field. I'm guessing that the warbly effect suggests that at that point the two regimes are not in a simple harmonic relationship. Certainly the Top 1 at 647 is a long way from half the Bot 2 at 1242 Hz!
Can you fill in data points between the top and bottom of each regime, please. The goal here is to be able to plot frequency as a function of air speed out of the windway, so enough points to show the shape of the curve. The low end of the first regime should be particularly interesting. The format you give above is good.
OK, how does this look? I've arbitrarily gone with a total of 5 points per regime, picking round numbers as they are easier to set on the Flow Gauge(s). And avoided going below 6 L/min as I thought we'd cast doubt on the accuracy any lower. But let me know if you'd like me to go lower and by how much (in flow or Hz terms).
Code: Select all
Feadog Mk1 with 243.6mm blade to end of tube, 5 April 2023
Regime Flow Press Hz
Bot 1 6 5 600
Lo 1 7 7.5 628
Med 1 9 13.5 641.1
Hi 1 10 17 645.2
Top 1 10.9 20 647
Bot 2 11.8 23 1242
Lo 2 14 34.5 1268
Med 2 17 48.5 1281.5
Hi 2 19 62 1290.5
Top 2 22 75 1296
Bot 3 17.6 52 1865
Lo 3 22 72 1899
Med 3 26 104 1916.5
Hi 3 30 143 1933
Top 3 34 182 1947
Bot 4 25.5 106 2505
Lo 4 30 140 2532
Med 4 36 201 2556
Hi 4 40 264 2575
Top 4 >40 370 2602
It will be interesting to see if other whistles follow the same general pattern, or if this one is different for perhaps reasons of voicing.