Blowing machine

[trill]

. . . this video by Phil Bleazey and thought it might be meaningful to readers of this thread. . .

That video was a joy to watch.

Such clear, simple descriptions.

Really admire the craftsmanship.

Wish I could afford one !

edited to add: hit 4 separate registers without breaking a sweat ! Magical knowledge of the shapes needed to produce the sound !

[stringbed]

It's pretty ancient magic.

Here’s how far you can get without fingerholes,

https://youtu.be/ezureVn-cJQ

and here’s how such instruments are made

https://youtu.be/gqrbwOR4KeQ

[stringbed]

Phil's approach is (I think) similar to that used by fine Recorder makers. (The results, not necessarily the methods.)

The floor of a recorder windway is normally a raised platform on the block. The block can therefore not simply be made from round stock or turned on a lathe, as appears to be the case in the video (chamfer and all). This permits the radial curvature of the windway to be set intermediate between that of the bore (at the windway exit) and none at all. This freedom is propagated to the edge and, more importantly, permits the underside of the ramp to be at an adjustable angle to the axis of the air column without forgoing the arching.

As to the method of broaching the windway (and note the tapering of its sides): https://youtu.be/lxzO5Kvo7gk?t=780

[Terry McGee]

Of course you are right, which has me wondering where have I seen a block that is essentially round but has a flattened top? And how could you guarantee it to always go in with it's flattened top parallel to the ceiling of the windway. Keep trying, I guess. Hmmmm....

Ah, yes, the verb "to broach". I hesitate to broach the subject, but I have heard that expression in regard to cutting windways before. And yet it doesn't fit with normal engineering practice does it? I think of a broach as a long multitoothed tool such as used to cut keyways, eg:



Whereas the sneaky thing about the tool we've been looking at is that it can cut a scalloped trench. Which of course rules out the kind of broach shown above. But I note that the Von Huene people use the term, eg see from 12:50 in this video:

https://www.youtube.com/watch?v=lxzO5Kv ... hop%2CInc.

Note that their cutter allows you to move the tool left and right as well to cut a lateral taper at the same time.

I guess although the tool is very different, the action of the driving machine is similar to the classic broaching machine, and so the term has followed over.

I stumbled upon another recorder making video showing another single point cutter, see at about 5 minutes into:

https://www.youtube.com/watch?v=4KH7Lj6 ... erWorkshop

Note the flashing image at right of screen showing that both ceiling and floor seem to be getting the scalloped treatment.

We shouldn't overlook the amount of stuff available about making recorders in our quests to make whistles!

[stringbed]

Ah, yes, the verb "to broach". I hesitate to broach the subject, but I have heard that expression in regard to cutting windways before. And yet it doesn't fit with normal engineering practice does it? I think of a broach as a long multitoothed tool such as used to cut keyways

That basic type of broach is commonplace in the recorder maker’s toolbox. It’s seen in motor-driven use here.

I stumbled upon another recorder making video showing another single point cutter, see at about 5 minutes into:

https://www.youtube.com/watch?v=4KH7Lj6ald4

You’ll see a broach used manually if you slow down the playback speed of that video to 25% in the segment labeled “Widen the wind-way”, here. If it’s of any interest I can describe how they’re used to cut an entire windway by hand.

[Terry McGee]

Hi all again

Sorry for lapsing quiet, too much going on! Hey, at my age, aren't I supposed to be at risk of boredom?

Still puzzling about how we define the low end of the 1st Regime. I unearthed my old Type II Sound Level Meter, and wondered if it would reveal anything. Type II is "industrial grade", whereas Type I is "laboratory grade". Probably good enough for our immediate purposes.

I've talked before about the lab acoustics not really being ideal for sound measurements. So instead of following the classic "1 Metre on Axis" approach, I just put it down on the desk 200mm (8") away from the whistle's window. And not even on axis, as that would make reading the meter harder. If we decided it is a necessary feature in future, I could play with the location of the various items to optimise ease of use and quality of results. But let's see what it tells us, if anything.

Things to note:
- couldn't measure the lowest flow rates, so just marked them <2 and relied on Pressures
- Included a zero flow line, to note the Sound Level Meter's background reading. I'm using it on "slow" and "dBA". A background reading 10dBA lower than any other reading is fine.
- Noted that it rose to 46 dBA Slow or 60dBA Fast while the compressor was running! That's OK, I'm happy to wait!
- I used the Old Gen whistle, note it too has what appears to be a higher pitched Aoelian regime below the start of the 1st, but it's much less noticeable than on the Feadog Mk1 I'd investigated previously. Probably a voicing issue, but not noticeable in use. Nobody blows that low!
- Note when the 1st Regime kicks in, it's again at a very low frequency and volume level, rising a long way in both till it snaps into the 2nd regime.
- I didn't go much into the 2nd Regime, as I was interested to see if we would see Hysteresis going back down in flow rate. It appears that we do, whereas I don't think that was the case with the Feadog. Unless perhaps I didn't investigate that thoroughly enough.
- the point 5L/Min, 8mm Pressure, 571Hz and 71dBA looks like a possible "practical" bottom end of the 1st Regime. But identifying it on the run wouldn't be easy!

Code: Select all

Old Gen D, 6 holes covered, 23 May 2023		
				
Flow	Pres	Hz	dBA	Regime
0	0	0	20	
<2	2.5	575	52	Aoelian?
<2	3	370	30	1st
<2	4	496	28.5	
<2	5	544	39.6	
2	5.5	548	42	
3	6.5	563	60	
4	7	568	63.5	
5	8	571	71	
6	10	575	74	
7	13	578	77	
8	17	581	79	
9	22	1137	84	2nd
10	29	1147	89.5	
9	22	1135	85	
8	16	1092	73	
7	12	576	76.5	1st

Thoughts anyone?

[Tunborough]

Thanks, Terry. That should be interesting when I get a chance to plot it, but that may not be until next week. Meantime, when you get a chance, I'd be interested in what happens in the next couple of registers, too.

[Terry McGee]

OK, pushed on a bit.

Things to note:
- Hysteresis noticeable at each transition
- When plotting, good to use one colour for low to max flow, and another colour for the reducing flows. Otherwise it's confusing! Are we coming or going?
- Note that the volume seems to get a bit tied up with hysteresis too, with the volume dropping just before regime failures on the way down.
- I believe I noticed some sensitivity to my position in the upper flow volume readings. This would make sense as the wavelengths there are shorter, and my broad chest (OK, rounded tummy) can be expected to mess with the sound field more.
- Not sure if the Volume (dBA) data is of much help. But if so, I can investigate the body position sensitivity futher and look for solutions.
- Interesting to note that most of the whistle range above the First Regime exceeds the 85dBA level set down as the maximum level for an 8-hour day. So don't play your whistle all day!

Code: Select all

Old Gen D, 6 holes covered, 23 May 2023, extended 26 May				
				
Flow	Pres	Hz	dBA	Regime
		0	20	
<2	2.5	575	52	Aoelian?
<2	3	370	30	1st
<2	4	496	28.5	
<2	5	544	39.6	
2	5.5	548	42	
3	6.5	563	60	
4	7	568	63.5	
5	8	571	71	
6	10	575	74	
7	13	578	77	
8	17	581	79	
9	22	1137	84	2nd
10	29	1147	89.5	
11	33	1152	93.4	
12	39.5	1155.5	95	
13	47	1158	96.6	
14	56	1162.5	98.5	
15	62.5	1723	99	3rd
16	68.5	1727.5	99	
17	79	1733	99	
18	87	1738	98	
19	97.5	1742	96.3	
20	116	1746.5	95	
22	120	1747.6	98.3	
24	143	2314	105	4th
22	112	2302	102.4	
20	113	2300	100.7	
19	96	2288	98.2	
18	85	2279	97	
17	76	2270	96	
16	69	2257	93	
15	59	1722	93.5	3rd
14	51.5	1715	92	
13	45	1704	90	
12	38	1678	80	
11	32	1151	92.5	2nd
10	27.5	1147	90	
9	21.5	1135	87.7	
8	15	1086	58	
7	11	576	76.9	1st
6	8	572.5	74	
5	6	568	70.8