Competitive benefits of conical and cylindrical flute bores?

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Re: Competitive benefits of conical and cylindrical flute bo

Post by kkrell »

Terry McGee wrote:(McGee-flutes Genetic Division is working on breeding a new sub-species of humanoid optimised for simple-system flute playing. You'll spot them easily once released. Their knuckles drag in the dust.....)
Some would say they are already to be found in the wild. :lol:
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Geoffrey Ellis »

Terry McGee wrote:
keithsandra wrote: I'm only puzzled that the size and placing of my cylinderical flute's tone holes practically match my conical flutes.
Heh heh, there's a really good reason for that. They are about as far apart as a normal mortal will want to reach. Remember all "simple-system" flutes are a compromise on tone-hole spacing. If they weren't, the holes would be a lot more similar in size.

(McGee-flutes Genetic Division is working on breeding a new sub-species of humanoid optimised for simple-system flute playing. You'll spot them easily once released. Their knuckles drag in the dust.....)

I've done some playing with the Cylinder bore, e.g: Image

You can see how the hole sizes vary just as our usual conical flutes vary. And, for the same reasons. Because they are so much smaller than the Boehm flute's holes, we still get a lot darker tone than the keyed Boehm's.

Geoffrey & Paddler, looking forward to hearing more about your work. So much more to be done with flutes!
That's a nice looking flute, Terry!

Yes, the finger hole spacing on the cylindrical bore/tapered head flutes I'm making is very close to the conical bore flute, but there is another difference in that the entire set of finger holes is farther down the bore than on a conical bore flute. So the player has to reach farther out for them, and this can be problematic for players who already have to stretch a bit for the conical bore instruments. I made an experimental Bflat tuning in this cylindrical bore style, and it is probably unplayable by most people. I'm 6'3 with very long arms for my height and I can barely play the thing, so I don't think it would find many takers! Not comfortable at all unless the player is willing to use the piper's grip like the bansuri players do.

And as Paddler mentioned, the average hole size is a bit bigger than on conical bore flutes of the same key. This became necessary in order to get the intonation balanced. I'm working on tweaking a couple of holes just a trifle smaller, but if I go too small then suddenly the first and second octave tuning begins to drift apart...

This is why the bansuri works so well on intonation. Those holes are huge, ranging between 11mm and 13mm in diameter, and they are spaced in such a way as to favor the tuning over the player's comfort! Hence that splayed out piper's grip, without which they are unplayable. And of course the timbre of the instrument is totally different from the smaller bored flutes made for ITM.
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Re: Competitive benefits of conical and cylindrical flute bo

Post by keithsandra »

Re. Geoffrey's post on positioning of sets of holes. The positioning of the six holes on the conical and cylindrical flutes I'm comparing are the same. The cylindrical tone holes are bigger.

The price of the new flute is encouraging. When can we have an expert review of the final model with photos?

Thank you for your helpful info Master McGee. But rather than lengthen fluters' arms what about lengthening fingers by simply adding extra one inch finger knuckles?
Would that do it? Saves new tailoring costs too.
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Geoffrey Ellis »

keithsandra wrote: The price of the new flute is encouraging. When can we have an expert review of the final model with photos?
Hoping to have photos, sound samples and possibly video on my new website before the end of the month.
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Matt NQ »

I'm curious that there has been no mention of the Fajardo wedge solution for cylindrical bores in this thread. What's the latest thinking on its advantages & disadvantages?
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Re: Competitive benefits of conical and cylindrical flute bo

Post by an seanduine »

Most Tipples are sold with wedges.

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Re: Competitive benefits of conical and cylindrical flute bo

Post by Geoffrey Ellis »

Matt NQ wrote:I'm curious that there has been no mention of the Fajardo wedge solution for cylindrical bores in this thread. What's the latest thinking on its advantages & disadvantages?
I did a lot of experimenting with variations on the Fajardo wedge. They certainly worked to a point, but I didn't completely love the way they affected the flute. They definitely helped with the intonation issues, but getting them just right was tricky, and I found that the flutes that had them felt somewhat less "free blowing". Also there were difficulties with introducing them into the bore in a permanent way. For a flute that I intended to be a single piece of wood with a permanently fixed stopper, the conventional wedge design would not work. I actually evolved into doing them from poured epoxy. I would put a measured amount of clear epoxy against the stopper in the headjoint and then tilt the flute just the right amount and leave it to cure. This caused the epoxy to pool at the head and form a natural wedge. Once I dialed it in it worked pretty well in terms of reproducing the wedge, but I never loved it. Much better than having nothing, for sure.

When I started reaming out the headjoint area with a parabolic tapered reamer, the improvement was subtle but noticeable. Plus it was a lot more reliable and consistent. Despite that, if I did not have access to a parabolic reamer I would absolutely use this method over leaving the bore a straight cylinder. The wedge was a clever invention, but for any maker who has the ability to ream the headjoint of the flute I'm not sure why they would bother with the wedge. But if I were making flutes from PVC then I'd put a wedge in them.
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Terry McGee »

Geoffrey Ellis wrote:That's a nice looking flute, Terry!
Thanks, yes, I was happy with it. Note the thickened sections at the joints. I've noticed a lot of 19th century cylindrical flutes show cracking at these points because the bore is so big and they wanted to keep the outside diameter comfortable. So keep an eye on that issue.
And as Paddler mentioned, the average hole size is a bit bigger than on conical bore flutes of the same key. This became necessary in order to get the intonation balanced. I'm working on tweaking a couple of holes just a trifle smaller, but if I go too small then suddenly the first and second octave tuning begins to drift apart...
And if that tuning drifts too much, not only does tuning of the instrument suffer, but so does response. So important to attend to it.

You might want to experiment with a different head taper as an alternative to making the tone holes uncomfortably big. I have no reason to believe that Boehm's head taper is magical. I'd guess is that it worked for him with the size of holes he chose. We know that no taper (i.e. simple cylinder) makes for very flat harmonics. So more taper would presumably give sharper harmonics, and permit smaller holes.
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Terry McGee »

keithsandra wrote:Thank you for your helpful info Master McGee. But rather than lengthen fluters' arms what about lengthening fingers by simply adding extra one inch finger knuckles?
Would that do it? Saves new tailoring costs too.
Indeed. But why stop at the number of joints per finger? What about more fingers? Suddenly the perennial flutemakers' dream of a keyless chromatic flute is within grasp.....

But with which of your four hands should you grasp it?

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I have a little bronze of Shiva in my office given to me many years ago by a friend. She said "I thought you could probably do with a hand in the workshop".
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Terry McGee »

Geoffrey Ellis wrote: I did a lot of experimenting with variations on the Fajardo wedge. They certainly worked to a point, but I didn't completely love the way they affected the flute. They definitely helped with the intonation issues, but getting them just right was tricky, and I found that the flutes that had them felt somewhat less "free blowing".
I think you are spot on there, Geoffrey, and I suspect I know the reason (but could be wrong!).

For those unfamiliar with the Fajardo wedge, it's a wedge cut out of a cylinder, inserted into the top end of the flute head. The idea is that it takes up some of the airspace in a cylindrical head, more at the stopper end and fading out as you approach the bottom of the head, thus making it look like a tapered head. As Geoffrey says, this helps the intonation in the same way as a tapered head helps the intonation in a Boehm flute.

But, consider a cross-section cut through at the embouchure hole. The bore won't be round, it will be D-shaped. And remember our flute is side-blown, so the top end of the vibrating air column has some spiral elements. I'm guessing that our D-shaped bore is introducing some aerodynamic inelegance.

Not convinced? Try this simple test. Drop a bamboo kebab skewer into the foot of your flute so it ends up resting against the stopper. Now try to play it.....

I did think of another work-around for those not wanting to go to reaming. You could make a tapered former, grease it well with release agent, poke it up the cylindrical head, and pour epoxy or something similar into the stopper end. After the potting agent dries, you remove the former, leaving a nicely formed tapered bore.

But hey, Geoffrey is right. Reaming is no big deal and much less mucking about!
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Geoffrey Ellis »

And if that tuning drifts too much, not only does tuning of the instrument suffer, but so does response. So important to attend to it.
Yes, the cylindrical bore flutes seem to want slightly bigger holes in general to play well and in tune. Plus it gives the flutes a big voice, which might be desirable in some instances. Blayne described one of these as a potential "session cannon" because the voice was so strong and could be pushed. But I suspect most ITM players who play in sessions are going to lean toward the conical bore versions, simply because it's familiar and traditional.
You might want to experiment with a different head taper as an alternative to making the tone holes uncomfortably big. I have no reason to believe that Boehm's head taper is magical. I'd guess is that it worked for him with the size of holes he chose. We know that no taper (i.e. simple cylinder) makes for very flat harmonics. So more taper would presumably give sharper harmonics, and permit smaller holes.
It's funny you should mention this, because I have at times pondered on the subject along the way as I messed about with different ways to introduce the taper. It was that bamboo flute that got me thinking because I'm quite confident that the natural taper in that piece of bamboo does not follow the ideal as outlined by Theobald Boehm. And yet it works beautifully. So it would make for an interesting experiment to try variations on the taper. The thing that would inhibit this experiment (and most makers who create their own tooling will appreciate this) is that making reamers is a lot of work! To experiment with a bunch of taper variations means manufacturing a bunch of reamers which is not an easy thing to fit into a busy schedule, especially when there is no certainty of an improvement.
But, consider a cross-section cut through at the embouchure hole. The bore won't be round, it will be D-shaped. And remember our flute is side-blown, so the top end of the vibrating air column has some spiral elements. I'm guessing that our D-shaped bore is introducing some aerodynamic inelegance.
Exactly! My feeling was that by introducing the taper and creating that D-shape it introduced some type of turbulence or resistance to the easy flow of air. I tried to counter this by moving the taper around a big in relation to the embouchure hole, but it didn't change anything much. Again, it was not so bad as to be a deal breaker, but when I compared it to a reamed head I could tell the difference.
I did think of another work-around for those not wanting to go to reaming. You could make a tapered former, grease it well with release agent, poke it up the cylindrical head, and pour epoxy or something similar into the stopper end. After the potting agent dries, you remove the former, leaving a nicely formed tapered bore.
Definitely a workable solution. You'd have to come up with a reasonable method of centering the former in the bore in a way that would still allow you to introduce the epoxy, but that is do-able.
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Tunborough »

Geoffrey Ellis wrote:It's funny you should mention this, because I have at times pondered on the subject along the way as I messed about with different ways to introduce the taper. It was that bamboo flute that got me thinking because I'm quite confident that the natural taper in that piece of bamboo does not follow the ideal as outlined by Theobald Boehm. And yet it works beautifully. So it would make for an interesting experiment to try variations on the taper. The thing that would inhibit this experiment (and most makers who create their own tooling will appreciate this) is that making reamers is a lot of work! To experiment with a bunch of taper variations means manufacturing a bunch of reamers which is not an easy thing to fit into a busy schedule, especially when there is no certainty of an improvement.
WIDesigner, available on GitHub, can model the effect of a tapered head joint on the tuning of a cylindrical flute. While the flute model is still a prototype, it may help you identify general trends without the need for a pile of reamers and trial head joints.

The current taper optimizer solves the opposite problem to yours: optimizing the conical bore of the body for a cylindrical (or at least fixed taper) head joint. If you find the flute model useful, I can add a head joint optimizer for you, or even a full-on bore diameter optimizer like the one in the reed study model.

I applaud the experimentation you're doing. I'm glad you've landed on a model you're happy with.
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Matt NQ »

Terry McGee wrote: For those unfamiliar with the Fajardo wedge, it's a wedge cut out of a cylinder, inserted into the top end of the flute head...
But, consider a cross-section cut through at the embouchure hole. The bore won't be round, it will be D-shaped. And remember our flute is side-blown, so the top end of the vibrating air column has some spiral elements. I'm guessing that our D-shaped bore is introducing some aerodynamic inelegance.
Thanks Terry and Geoffrey for your most illuminating comments on the Fajardo wedge. Still interested myself as I don't have the tools or ability to make reamers (and I probably should disclose I'm setting out to make whistles not flutes). I'm curious about the "D-shaped" cross section after wedging that both of you have talked about (the pouring epoxy method you mention Geoffrey would produce a flat topped wedge and thus a D cross section). My understanding is that the normal Fajardo wedge is cut out of a hollow cylinder, which presents a curved with flat edges profile toward the embrouchure hole in a flute or the window of a whistle, not a D shape. I'm curious that you found the flat topped wedge (with the poured epoxy) worked best, Geoffrey, despite that it would seem logical that a flat topped wedge is further from a parabolic reaming and likely to create more "aerodynamic inelegance" than the curved with flat edges profile of a tapering wedge cut diagonally from a hollow cylinder? Or perhaps I've misunderstood something here? :)
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Re: Competitive benefits of conical and cylindrical flute bo

Post by Terry McGee »

Tunborough wrote: WIDesigner, available on GitHub, can model the effect of a tapered head joint on the tuning of a cylindrical flute. While the flute model is still a prototype, it may help you identify general trends without the need for a pile of reamers and trial head joints.

The current taper optimizer solves the opposite problem to yours: optimizing the conical bore of the body for a cylindrical (or at least fixed taper) head joint. If you find the flute model useful, I can add a head joint optimizer for you, or even a full-on bore diameter optimizer like the one in the reed study model.

I applaud the experimentation you're doing. I'm glad you've landed on a model you're happy with.
Hi Tunborough

Forgive me if we've been here before (I am old enough to have a Papal Dispensation to pull this concession!), but tell (or remind!) me what the philosophic basis of your app is. Does it derive from Paul Dickens' work at UNSW, based on their acoustic impedance spectrometer, or drawn from some other source?
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