Rockstro

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Terry McGee
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Re: Rockstro

Post by Terry McGee »

paddler wrote: Wed Aug 10, 2022 3:39 am The value of a wider bore was well recognized by at least one baroque flute maker as early as the mid 1700s.
Johan Joachim Quantz (1697-1773), a hugely influential flute maker, was famous for such things as inventing
the tuning slide, and designing flutes with two separate keys for D# and Eb, but his flutes also had a larger bore
than was common at that time, or today, or any time in between.
Indeed. Later makers, eg Potter with his Patent Flute, reduced the bore to around 19mm to extend the range beyond what was needed in Quantz's time. http://www.mcgee-flutes.com/PottersGerm ... Patent.htm
I have a set of detailed plans for several of Quantz's flutes, and notice that he used a head bore of 20.4 mm!
This particular flute had several corps de rechange (interchangeable upper body sections for use when playing
at different pitch standards), and the widest point in the bore for each of the body sections varies from 20.3 mm
for the smallest, to 20.5 mm for the largest. This is for a D flute, but it is pitched lower than modern standards.
The intention seems to have been to optimize the bore for something close to A=392, which is more like a
C# flute at A=440 hz, but the interchangeable body sections allow the pitch to be changed up to A=415 hz for the
shortest section. Whichever way you look at it, this is proportionately a very large bore.

Also, note that this is a conical bore flute, not a cylindrical bore, parabolic head, Boehm-style flute, so it is quite
applicable to the conical bore Irish flute designs we use today. Quantz flutes are reported to play very well across
the full range of notes used in baroque flute music, so definitely beyond what we typically use in ITM in the upper
registers.
Which all, interestingly, makes it very similar to my larger bore version of a C flute. It's scaled up from a typical Rudall & Rose Bb flute, with a head bore around 20.9mm. It has a lot "bigger" sound than my other approach, scaled down from a Rudall D flute. And covers the range we need comfortably.
Given the extraordinary level of sophistication and attention to detail in Quantz's work (it could even be argued,
far surpassing anything since!) I think it lends considerable weight to the argument that there is merit in a larger
than standard bore. For a deep dive into Quantz's mindset and level of mastery of all things flute-related, you can read
a translation of his original 1752 treatise "On Playing the Flute" (400+ pages). It contains an absolutely mind-boggling
level of detail about flute playing, performance practice, tuning standards, etc. After reading it I was left with the
feeling that almost everything we think of, and a lot that we have not thought of, has already been thoroughly explored
hundreds of years ago ... and written up, published, patented, built and sold. :boggle:
I was also left with the strong impression that Quantz didn't do anything by accident.
Heh heh agreed, Paddler. We think we're pretty cool working from well-developed 19th century originals, ironing out the bugs they left us (and the bugs accrued over the intervening period). But Quantz and probably some of his contemporaries were developing the conical bore from the previous renaissance cylinder bore flutes. With none of the advantages we have at our fingertips!

I've played this flute of Quantz in the Library of Congress back in the 70's. The Curator had a lunch appointment and left me there with instructions to close the door when I left. I believe they don't let you do that any more! Note the adjustable screw stopper, the tuning slide and the enharmonic D#/Eb keys, all Quantz innovations. And an extraordinary number (6) of corps de rechange to meet anything likely to be thrown at you, expecially when combined with a tuning slide! The flute is believed to have belonged to Quantz's student Fred the Great. I'm sure he could afford it! Image

More about Quantz at: http://jjquantz.org/flute-builder/

So what with the evidence from both Quantz and Boehm, I think we have developed the prima facie case for trying the larger bore for Irish D flutes!
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Re: Rockstro

Post by GreenWood »

I said... "Maybe the 14mm piccolo would have liked a different shape bore, slightly flatter"... which would also make it narrower... urm....

The closest working flute I have of that length here, besides a little swisspipe at around 12mm, is a small recorder. It is conical and the head is around 13mm. So I used that as example. I will first write down how I understand how octaves and harmonics work. I don't say it is the correct or complete way.

The length of the flute sets the lowest wavelength possible, the lowest note. It does not do anything else, but that length does provide some resistance in air flow regarding higher notes, it also provides a slight reflection of frequency/sound.

The oscillation of a note is set by two things, the resistance at embouchure (which is speed of air combined with resistance at embouchure due to resistance along bore ) , and the natural form the resulting oscillation settles at (your note or harmonic, which are set by length to aperture combined with what overall pressure/resistance you are working at, ie. to achieve octave).

Harmonics are notes, they aren't "extras". When, without blowing harder, lifting top finger gives D second octave for example, though the overall resistance decreases (which should lower a note) , that decrease is at a point which shortens the distance to aperture closely enough to where D2 would be as tonehole that that harmonic is sounded as note.

When blowing from say E to an intemediary harmonic and then to E2, the wave form finds best fit along the way to E2 according to pressure used, which is the harmonic along the way. The harmonic is a note. Flutes are tuned for octaves, so harmonics might seem slightly weaker for that (the toneholes are placed and shaped with octave sound as priority).

One way to visualise the pressure idea is a bouncing ball "D........d......d....d..d..d.d.ddddd". Here, the pressure difference becoming relatively smaller when working at higher pressure (higher air speed) equates to how fast the ball bounces when nearer to the ground.

So, the frequency the flute settles at at any point is set by the closest note/harmonic it can find under the (pressure) circumstance , that natural resonance helping set/refine the (pressure) frequency of "bounce" of the ball. That is because the tuned resonance is a physical parameter based on reflected distances of the initial untuned sound, i.e. to the aperture, or derivatives of that distance.

The above isn't new, it is well understood in other description or by other manner of description since whenever. The point I am making though is that the resistance along the flute is very important in forming notes and their harmonics, because it sets how easily an approximate "pressure only" based frequency is able to be reached . Most texts describing flutes settle more on distances, and where pressure is involved it is "speed of air", or adjusting or aligning pressure nodes, or "how hard a flute is to fill".

So going back to the piccolo (recorder on my side), basser notes like wider bore to sound full. There is physics available for why this is so, optimal bore size for any note for example. I will skip that and just think of it in terms of pressure. Smaller bore for higher note also means more resistance along the bore, which is also air pressure resistance at embouchure, so helping the shift to that higher note by the equivalent of the ball bouncing closer to the ground. If there is not enough resistance, then you simply will not find that note, at best some shrill remnant that lacks any greater interaction with the bore, an interaction that provides the depth and fullness to a note we so much like.


On the recorder I have, the top three second octave notes are difficult, by closing various of the (already small) toneholes below, they play clearly. To say I am only finding harmonics that way would not be fair, what is being done is that both the "reflection" from the lower part of the flute is being changed slightly, as well as the pressure along the bore being increased. To verify this properly someone would maybe have to build a piccolo or similar to say C# length, with cylinder at say 14mm, and conical parts at reducing sizes, till they found one that played C# in second octave easily and cleanly....or just by messing around stopping up an existing 14mm piccolo in various ways. If that note is found, then the rest of the flute can be built around achieving that, which would probably be more fun than it sounds because we tend to want a more open bore lower down for the bass notes. The only way I can think of is by keywork, or just possibly very careful placing of toneholes to encourage harmonic... even a stopped end would increase pressure (lower toneholes would then be large to achieve their sound but resistance would still increase with higher pressure topnotes due to no linear venting)... but that would be losing a note as well. Just possibly smaller embouchure would work as well, because it would then hold a slightly higher pressure in that space directly from air flow. Also working with volumes relative to note, either total bore volume or between embouchure and tonehole might just give a note an advantage.

Again, the above is not to be taken as empirical, it is one way of thinking about how flutes work and is not nescessarily accurate.


Paddler

I also have plans for a flute of Quantz and hope to make one.

I will drop in a link here because it is relatively new, I guess you both have watched it.

Boaz Berney on simple system flutes of Boehm

https://m.youtube.com/watch?v=4FbFQK-LqZI
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Re: Rockstro

Post by dunnp »

Interesting discussion here.

Just to say Peter Noy made a flute with a 20.8 mm head bore.
It was posted on his Facebook account years ago. Like all his instruments it was a beauty with 8 keys I think.

I can imagine it was a blaster. I owned another Noy for a while fantastic flute. It had a large bore too but I don’t think it was anywhere near the one he advertised with a 20.8 mm bore.

Take care
Patrick
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Re: Rockstro

Post by dunnp »

https://www.facebook.com/media/set/?set ... 485&type=3

Here’s a link to the Noy flute not sure it will work.
GreenWood
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Re: Rockstro

Post by GreenWood »

I almost ended up with a 20mm bore just now, actually part of it is slightly over that.. will write up on it.

How is it whistles manage wide bores relative to length ?

I was reading up at an alto flute site and (if I remember) they were saying Boehm had been looking for a purer fundamental note sound by widening the bore, while clips in

https://books.google.pt/books?id=qtpwui ... &q&f=false

underline the seemingly opposing search for higher octave range in classical flutes.
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Geoffrey Ellis
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Re: Rockstro

Post by Geoffrey Ellis »

GreenWood wrote: Sun Aug 21, 2022 9:22 am How is it whistles manage wide bores relative to length ?
To some degree I would guess that thin walls and (relatively) large finger holes are a factor. Both of those design characteristics improve second octave tuning on a cylindrical bore instrument, and both are features of the Boehm flute design (though I'm not so sure about the wall thinness piece because there are risers under the keys). A larger finger hole does a better job of bridging the optimal hole location for the first and second octave (which are slightly different). Optimal finger hole placement for the second octave would be slightly farther down the bore than the first octave. A large hole (or an oval shaped hole) can bridge both locations and allow for better tuning. If you took a thin walled whistle and made small finger holes (relative to the bore size) you'd have a flat second octave.

For a balanced and responsive 2 1/2 octave range, the aspect ratio of your bore (cylindrical again) needs to be around 30-32:1. 32:1 is better, but most whistles that I've seen use a much lower aspect ratio. More like 25:1 or a little higher. I expect that a lot of players like this because it gives a robust and full first octave (just like Boehm's 20mm bore), but at the expense of the third octave. And the second octave might not be as responsive either. I have not played a wide variety of low whistles, so I don't know how well most of them do in the third octave, or if they get played much up there. But if you are making a "mostly two octave" whistle, then you can have a low aspect ratio, thin walls and big holes and get a nicely tuned instrument I think.
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Re: Rockstro

Post by GreenWood »

Thanks Geoffrey.

I read somewhere about cylindrical octave discrepancy (in say Rennaisance flutes) being overcome by thin wall and larger tonehole in Asian flutes or similar, but was not sure on that. So the point is that whistles tend to be smaller, so allowing a larger relative (keyless) tonehole size to bore. The boehm flutes do have the parabola for tuning, but the wider venting area allowed by wider toneholes must help even if wall thickness is large, as well as for tone. Additionally baroque and rennaisance flutes favoured small toneholes, Rennaisance flutes being notably flat for upper second octave, and the conical bore flutes allowing better tuning.

I'm just wondering what the practical limits are. Terry mentions difficulty with his very wide conical bore piccolo for top of second octave (very roughly e.q 28mm conical on D flute) .

As I don't know how to calculate conical ratio of diameter vs length I will just link a chart for cylindrical

https://www.music.bracker.uk/Music/Sear ... -Bore.html

which gives 23mm ideal for D note on a flute... but even 19mm is well wide for top of first octave.

https://tippleflutes.com/flute-embouchure/

Says he uses 20mm bore (thin wall) and apart from tuning (needing a wedge?) seems accepted as playable ?

So, sort of talking in circles here, large bore makes tuning slightly more difficult for standard flute tonehole sizes, gives stronger low note fundamental, at an extreme makes upper second octave difficult.

If tuning is resolved by conical bore or parabola, then wider bore makes upper second more difficult to a degree and the overal tone less sweet in harmonic structure but possibly fuller via fundamental....


Terry, in my reply to your piccolo I confused your saying narrow bores were shrill with your saying wide bore high second octave being difficult, and was replying to difficult second octave being shrill (because forcing it usually gives a shrill note)....

....anyway, I have just made a boehm flute with parabola, with bore that is around 20mm or slightly larger . It has a roughed 8mm embouchure giving 3 octaves well for (untuned low) bass note, and no toneholes yet. Embouchure will be around standard. I will place toneholes starting slightly north of your boehm model Terry, by rough measurement from screen. If there is any particular point or sound you want me to record, or for me to study in detail, or even for me to try specific placement of any tonehole for comparison with 19mm bore, then say. I know that any recording will have discrepancy dependent on equipment. Otherwise I will just go ahead with "as best" estimates for the flute, then write down the build, the design, tuning values and sound recording that result, at the usual page.
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Re: Rockstro

Post by GreenWood »

The 20mm cylindrical bore with parabola seems fine. It is loud and my ears are still ringing a bit. Second octave is good too, not hard to reach and with some special harmonics to it. I left the embouchure around 10 by 9 mm because I was happy with it at that point. Octave tuning seems good also, with second easy to play and in tune from small tonehole till full size. At full size all toneholes ended up large, because I obviously didn't start with them shifted north enough to start off with for the wider bore...all are at 10mm approximately :-) ...playable but pretty much the limit. I will post up the build in a few days.
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