It is currently Mon Apr 06, 2020 9:55 am

All times are UTC - 6 hours




Post new topic Reply to topic  [ 145 posts ]  Go to page Previous  1 ... 6, 7, 8, 9, 10  Next
Author Message
 
 Post subject: Re: Rockstro
PostPosted: Wed Feb 26, 2020 11:16 am 
Offline
User avatar

Joined: Thu Sep 13, 2012 1:15 pm
Posts: 404
paddler wrote:
[
I have not seen chambering in cylindrical bore flutes. However, I do have an interesting bore profile graph of the head of a Rudall
Carte & Co, Radcliff system, flute that demonstrates quite clearly that even when reaming the parabolic head of cylindrical bore flutes
the bore profile was not smooth and regular.


I had a conversation with Mike Geoghagen, the former craftsman who made the Garner headjoints (before Brad Garner fell from grace). We met at the NFA convention in 2016 and talked about "tweaks" that are made to Boehm headjoints even today. He couldn't/wouldn't say too much about it for obvious reasons, but he did indicate that a lot of headjoint makers try to create their own special sauce when it comes to the headjoint. In the case of modern headjoints, I have heard a wide variety play-tested, I believe that much of this tweaking is largely just marketing hype. It doesn't mean that tweaks to the parabolic taper can't affect the flute, but that such effects are likely to be so minimal that they can't be perceived by most players. This is just my own suspicion based upon the level of competition among headjoint makers. I make the tried-and-true version following the exact specs laid out by Boehm and the serious players who have tried them love them, showing the Boehm knew what he was about.

Having said that, I would be curious to at some point try introducing some irregularities into the headjoint, just to see what happens :-)

_________________
Geoffrey Ellis Flutes


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Wed Feb 26, 2020 11:24 am 
Offline
User avatar

Joined: Sun Nov 16, 2003 12:27 pm
Posts: 1440
Location: Kingston WA
Irregularities happen in wooden instruments at least. Minor warping of the cross section, sanding or reaming the bore too much or not enough, normal aging. Trying to quantify these can be a challenge but in general I find some ovality is beneficial to tone production. Delrin makers take note - try to add some ovality to your bores with the vertical axis (fingerholes) being the greater. On wood however, the horizontal axis actually shrinks. Thus machine the bore smaller and add the ovality by sanding the vertical axis only. The sockets and tenons will stay round. It would be interesting to see if this makes a playing difference on these otherwise static instruments.

Casey

_________________
38 Years as a Flute Maker!
Coming Soon: An Ergonomic Low G flute!
http://www.caseyburnsflutes.com
http://www.folkflutes.com


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Wed Feb 26, 2020 4:10 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 7:19 pm
Posts: 531
Location: Hood River, Oregon, USA
Tunborough wrote:
paddler wrote:
I have not seen chambering in cylindrical bore flutes. However, I do have an interesting bore profile graph of the head of a Rudall
Carte & Co, Radcliff system, flute that demonstrates quite clearly that even when reaming the parabolic head of cylindrical bore flutes
the bore profile was not smooth and regular.
The modelling I did on cylindrical bore flutes for this thread, viewtopic.php?f=2&t=107840&p=1212419, suggested:

1) If you want a headjoint bored with a single reamer, without chambering, the model suggests a stepped cylinder to balance tuning across two octaves.

2) If you include chambering, the model suggests a rather dramatic hour-glass shape in the headjoint, with two big chambers, for balancing tuning across two octaves.


The Rudall, Carte & Co "parabolic" head has a kind of stepped taper shape. See below. The embouchure is at position 6.2 on the horizontal scale.
This head is especially interesting because it is made of ebonite, an so is not subject to the same shrinkage and distortions as wood.
This is not chambering, obviously, but it does lend weight to the argument that bore profiles are tuned in interesting, non-uniform ways,
even in flutes that have cylindrical body bores.

As for the profile of the body of such flutes, they have lots of fairly large chambers, namely one for each of the closed tone holes, so these would have to be modeled in
order to understand the precise impact of the various bore perturbations.

Image


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Wed Feb 26, 2020 5:01 pm 
Offline
User avatar

Joined: Sun Dec 12, 2004 4:12 pm
Posts: 2179
Location: Malua Bay, on the NSW Nature Coast
PB+J wrote:
So it's been established to my satisfaction at least that "chambering" was a real thing.

Did it get "lost" as the boehm flute replaced the conical bore flute?


Rockstro and Carte actually go into this, but in their typically less-than-clear way. Note that they are still talking conical (conoidal) derived from Boehm's 1832 conical, not his later 1847 cylindrical.

665. Improved Conoidal Bore by Rudall, Rose and Carte. In the year 1851, or perhaps rather earlier, Messrs. Rudall, Rose and Carte wisely ceased to make conoidal flutes after Boehm's model, and they brought out a new bore which greatly improved the tone, though its proportions only differed slightly; in actual measurement, from the fine one that had so materially assisted the fortunes of the firm.

The lines of the new bore were straight, there being no longer any necessity for resorting to "chambering [my emphasis]:" see §340. The following interesting remarks on the bore of the flute are extracted from the pamphlet of Mr. Carte (1851, p.21).

666. "It appears that Boehm's investigations, which led to his discovery of the parabolic head and cylindrical tube, arose from the circumstance that he could not obtain a tone so fine in the lowest notes of the old conical body, used in his first flute, as in the rest of the notes. . . . . Now, it is to be observed that Boehm's having failed to obtain the notes in question so perfectly with the conical bore as he afterwards did with the parabola and cylinder, is no proof that these notes were not to be obtained with the old shape. On the contrary, there are reasons to be given why he might be expected to fail in this respect. One reason is this: the Germans, although the original inventors of the ordinary flute, have ever been slow in experimenting with the bore. Experiments in this direction have been chiefly made in England. In France very little was done in this way before the introduction of Boehm's flute. The eminent performers also, both German and French, have always aimed rather at mere sweetness of tone than power. Very different has been the case in England. No performers have ever approached the English in the union of a rich and large volume with sweetness of tone, and it has, doubtless, been from the desire to obtain this, that so many experiments have been made by the English performers and manufacturers with different-sized holes and variations of the general bore.

667. "Tacet . . . . in the last century, experimented with large holes, as did also the late Mr. Nicholson's father; but the most important improvements as to the tone of the ordinary flute, especially those gained by variations in the bore, have been effected by Messrs. Rudall and Rose. Now it may easily be conceived that Boehm, who is a German, coming necessarily, as he did, to the subject without much previous experience with regard to the bore, and falling upon, or turning his attention to, the more scientific mode of shaping the tube before he had exhausted the resources of the conical tube, did not ascertain to the fullest extent the capabilities of the old shape. I am also convinced that this was the case by experiments which have lately been made. As it was thought that flutes of wood, of the parabolic and cylindrical shape, if made sufficiently thin to be held comfortably in the hands, would be liable to crack, and as some preferred the tone of the wooden flute, while others could manage the embouchure of it better than that of the same flute in metal, strenuous efforts have been made by Mr. Rose so to vary the proportions of the cone as to correct the defective notes mentioned as having existed in the first of Boehm's flutes; and so successful have been his efforts, that not only are these notes rendered equal to the others, but so much is the general tone of the instrument improved, that it becomes a matter of opinion whether the wooden flute with parabola and cylinder, or that with this improved conical bore, is now the better."

We have to keep in mind that both Carte and Rockstro are very biassed observers!

Quote:
Is it related only to the third octave? Or would it have value for a flute basically intended to play in only two octaves?


That again is yet to be proven, in my view. As I pointed out somewhere further up, there are a number of clear deficiencies in tuning in the first two octaves, but whether any of the claimed examples of chambering would address any of these positively (and without impacting elsewhere negatively) is something we have yet to investigate.

I don't remember if anyone above raised this other possibility. It's conceivable (but again, in my view, not proven) that some minor bore tweaking could assist in improving the quality and clarity of some notes, if not shifting their tuning. An example might be if you had a note that suffered a warble, or was poorly focussed compared to its neighbours. Such notes often have upper partials that are not well tuned to their fundamental. Nudge said upper partial even a bit in the right direction, and you might get a significant improvement for a small change.

You can experience this easily yourself by blowing the harmonic series on low E, without venting the Eb key. Hopefully your low E and 2nd octave E will be in reasonable tune. But you'll probably find that the 3rd and 4th notes in the series are clearly out. Now try again with the Eb key open. Conceivably, there might be bore perturbations that might improve the quality and clarity of the unvented low E. But we would need to find perturbations that didn't also mess with other notes.

Your thoughts on this Tunborough? If we get the model working well, can we use it to look for tweaks that might improve the quality, clarity and power of our weaker notes (typically A and E). As well as perfecting the tuning and answering all the other matters raised above, of course!


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Wed Feb 26, 2020 5:02 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 7:19 pm
Posts: 531
Location: Hood River, Oregon, USA
Back to the issue of chambering and the question of how and why one would use it, and whether it
was used historically. I found a very telling statement on page 497 of Arthur H. Benade's book
"Fundamentals of Musical Acoustics", 1976 (revised edition 1990).

The text quoted below is in the section on Perturbation Curves for the Flute, and it follows on
from an earlier, very detailed discussion, on pages 478 to 480, of the systematic process to follow in
order to use chambering and reaming to improve the tuning of a bassoon.

Anyway here is the quote:

"Sensitive playing experiments based on this phenomenon can be used to guide the adjustment of flute-type
instruments for good musical usefulness. The adjustments themselves are of course carried out in the manner reminiscent
of that described earlier for the bassoon. There is clear evidence that many leading makers of flutes and recorders in the
past knew a good deal about such techniques (though of course not in scientific terms). Curiously enough, the makers of
artistic-quality flutes today (with one or two individual exceptions) show very little knowledge of such methods, as evidenced
by the variable quality of the instruments many of them produce.
"

He has illustrations of how to use these functions, in the form of W curves for various modes of vibration for each given note,
showing how the curves align with the flute's bore (in this case for a conical bore flute). This is essentially what I referred to very
early on in this thread as building a map of the bore that shows where the nodes and antinodes occur. Here is an example:

Image

Anyhow, in the section about the bassoon that explains how tuning is done he talks about making modifications (via chambering
and reaming) to improve the alignment of the various modes of each note, and explains that this must be done in a specific order,
working down the bore, so as to not keep undoing modifications you have already made. He makes the following, very interesting
observation:

"One of the things that makes it possible to win such a game is the fact that air-column perturbations have their predominant influence on the lowest mode,
whereas perturbations in the proportions of tone holes are most active at higher frequencies. One makes sure the tone holes are plausible, corrects the bore,
and then trims up the tone hole sizes. It may be worthwhile to go through the whole process again if the quality of the instrument and the skill of its player
warrant the extra effort.
"


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Wed Feb 26, 2020 5:27 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 7:19 pm
Posts: 531
Location: Hood River, Oregon, USA
OK, finally, I find myself actually agreeing with everything in Terry's latest post! :thumbsup:

In the interests of space, I haven't quoted all of it, but I think the following part is on the money.

Terry McGee wrote:
I don't remember if anyone above raised this other possibility. It's conceivable (but again, in my view, not proven) that some minor bore tweaking could assist in improving the quality and clarity of some notes, if not shifting their tuning. An example might be if you had a note that suffered a warble, or was poorly focussed compared to its neighbours. Such notes often have upper partials that are not well tuned to their fundamental. Nudge said upper partial even a bit in the right direction, and you might get a significant improvement for a small change.


In my opinion it is more likely to be a matter of aligning harmonics to improve the tone and quality
of notes than the relatively simpler issue of tuning (for which I also have a lot of theories). This aligns
with what I just posted from Benade, and with my own personal practical experience in using chambering
at the foot tenon of a flute.

I had a flute that played great, but one day I noticed that it had a foot tenon that was considerably shorter
than the socket it plugged into. I thought, this is an egregious error on the part of the original maker,
and that it must surely be negatively affecting the flute. So, I set off on a several week long journey to "fix"
the problem. This involved making reamers so I could making replacement sections of the flute, testing,
tweaking, re testing etc. But every time I tested my "improvements" I would find that all of my attempts to
fix the flute by filling this chamber caused the bell note to speak poorly.

I though, ah, the foot must not be designed properly, so I went on to design and build an experimental foot
section that allowed me to dynamically adjust the locations of the vent holes in the foot, the length and shape
of the last section of the bore etc. I conducted a huge sequence of controlled experiments, but eventually,
what I found out was that the chamber at that location in the original helped align the harmonics such that
the note in question had a clear and resonant voice. Without the chamber it did not. Presumably, it was not
just the chamber that did this, but the overall bore profile that included this chamber.

By the end of all this my initial hubris had turned into respect for the knowledge of the original maker. There
are people out there (both past and present) who really know A LOT about how to make a good flute.


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 12:50 am 
Offline
User avatar

Joined: Sun Nov 16, 2003 12:27 pm
Posts: 1440
Location: Kingston WA
My point about warping exactly. See that illustration of a flute in Benade's book above? That flute is seriously warped!

With that much curving, there is no way to get those W curves to align.

Casey

_________________
38 Years as a Flute Maker!
Coming Soon: An Ergonomic Low G flute!
http://www.caseyburnsflutes.com
http://www.folkflutes.com


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 3:42 am 
Offline
User avatar

Joined: Sun Dec 12, 2004 4:12 pm
Posts: 2179
Location: Malua Bay, on the NSW Nature Coast
paddler wrote:
OK, finally, I find myself actually agreeing with everything in Terry's latest post! :thumbsup:

Damnit, I've clearly gone too far this time! (Tee-hee...)

And of course the same (but opposite) goes for bore distortion. If a small bore tweak in the right direction can assist a weak note, then an equally small bore tweak in the opposite direction could weaken an otherwise satisfactory one. The giveaway might be the direction. Hopefully, nobody would bother making a tweak that was either ineffective or not positive. Conceivably, some bore distortion might just happen to improve notes, but that's never been my experience, whereas I have found flutes just about rendered unplayable by serious compression. And returned to playability by steaming the compression out.

I've been trying to think of any other distortion sources we need to consider. You could imagine that rings might exert some compressive force, but those on sockets are not likely to affect bores dramatically. And the ring at the end of the foot has thick walls and a small bore under it, so probably isn't too influential.

But we do need to consider overall shrinkage, especially when say English-made flutes are subsequently measured in inland Australia or inland US. (Coastal areas like here probably have humidity levels more similar to London's, whereas Canberra's is about half.) We see that their heads and barrels are often cracked, and these cracks might gape a mm or so open. If the heads and barrels have shrunk that much, why wouldn't the body sections, and therefore the bore? A crack that wide would seem to suggest that had the conical section started out life as say 19mm to say 10.5mm, it would now measure 18.77 to 10.374. Spread that .22% shrinkage over the entire length of the bore, and we'd have to expect an outcome in tuning terms.

So these are all issues we have to be alert to. Can anyone think of others?


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 12:57 pm 
Offline

Joined: Sun Dec 05, 2010 2:59 pm
Posts: 1052
Location: Southwestern Ontario
jemtheflute wrote:
I strongly recommend that the participants in this thread read this article (you can sign up to JSTOR for a limited free readership): https://www.jstor.org/stable/25163825.
PDF copy available here, On Reaming Flutes.


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 3:54 pm 
Offline

Joined: Tue May 26, 2015 10:18 pm
Posts: 272
Empirical Math, or rather statistics.

There is the statistical solution to the problem of British airplanes being shot down during WWII. You could put shielding around the vulnerable areas of the plane, but how do you know what part of the airplane is vulnerable. The dead airplanes are the ones with holes in vulnerable spots. So, they took all the returned surviving airplanes and mapped the bullet holes onto a model. You only need to add heavy shielding to the blank spaces on the model.

Maybe you can collect all the "best" playing flutes, and then measure the bore perturbations and map that on a model.


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 6:08 pm 
Offline
User avatar

Joined: Sun Dec 12, 2004 4:12 pm
Posts: 2179
Location: Malua Bay, on the NSW Nature Coast
The Bigio and Wright paper is certainly very worth a read, but I find I do come to some different conclusions to those of the authors, particularly relating to the three Stanesby flute measurements. They feel that "the steps between the sections on flutes 264 and 281 were caused by the maker inserting the reamer further into the wood". If that were the case, we'd expect to see the same bore shapes slipped up or down the flute, but we don't. Note that those two flutes are ivory, the flute with the straighter bore shape (shown as the unbroken line) is lignum vitae. Lignum vitae is an extremely tough and heavy wood, while ivory is known for its shrinkage and instability (as illustrated by how many cracked ivery heads we come across and how many cracked ivory rings on wooden flutes we find.)

My conclusion is that the lignum vitae flute has more successfully (but not entirely) escaped the ravages of time and tenon compression, whereas the two ivory flutes are showing the classic hallmark shapes. I think we are at great risk when we draw assumptions from bore measurements without considering fully the effects of time and pressure.

Now, something you need to be aware of in interpreting these bore shapes. The top of the Stanesby LH section is a socket, not the usual tenon we expect in later days. And they have made 0 on the graph the bottom of that socket, the start of the conical bore. That explains why the first joint between LH and RH bore sections comes in at 180mm, rather than around 207mm as we are used to seeing. The junction between RH and foot bores occurs at around 310mm. You can see the bore is still reducing in diameter at the start of the foot, but has the classical flare for the last 60mm or so.

I'm imagining, incidentally, that the three identifying numbers for the three flutes are just Horniman's acquisition numbers, not Stanesby's serial numbers. So we shouldn't imagine they tell us which is the earliest or latest flute. I don't remember Stanesby using serial numbers, so we are unlikely to know which came first.

Interesting to speculate what the Rudall Carte reamer was for. 350mm long, 22mm to 17mm diameters over that length. A bass flute?


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 8:38 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 7:19 pm
Posts: 531
Location: Hood River, Oregon, USA
Terry, did you read the following paper on the JSTOR website (which you can access by signing up for a free
membership)? I think it is the one that you would be most interested in regarding methods of estimating
and compensating for shrinkage and other distortions:

Woodwind Instrument Bore Measurement by Cary Karp

One example method is to measure the ovaling present in an antique instrument, then combining that with
information about the ratio of tangential to radial shrinkage for the species of wood that the instrument is
made from. Assuming that the freshly reamed instrument had a round bore, then the more it has shrunk
the more oval its bore will be. If it is still round, then it either hasn't shrunk very much or it has been re-reamed.

On the issue of those cracked ivory rings on wooden flutes, I agree that there are a lot of them. It is interesting
that they were placed there to prevent the thin and vulnerable wooden sockets from cracking, but invariably,
that thin, vulnerable wooden tube cracked the ivory supporting ring that was shrinking against it. It shows that
wood is not so delicate and easily crushed! :poke:

I also read recently (and this is confirmed in the New Langwill Index) that when Heinrich Grenser died in 1813,
his workshop was inventoried, and the contents included 7 lathes, a polishing machine, 120 turning bits, 12
thread cutters, 43 reamers for flutes, 48 reamers for oboes, 10 reamers for clarinets, 1 for basset-horn,
35 for bassoon 14 for serpent, and a further 86 unspecified reamers!


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 10:29 pm 
Offline
User avatar

Joined: Sun Dec 12, 2004 4:12 pm
Posts: 2179
Location: Malua Bay, on the NSW Nature Coast
paddler wrote:
Terry, did you read the following paper on the JSTOR website (which you can access by signing up for a free
membership)? I think it is the one that you would be most interested in regarding methods of estimating
and compensating for shrinkage and other distortions:

Woodwind Instrument Bore Measurement by Cary Karp


Heh heh, not only did I read it, I read it at the time it first came out! 1978. I'd already been making for a few years, so it seemed perfectly timed for my guidance. But alas, I found it one of those extremely frustrating articles that offers lots and delivers nothing. He makes lots of bold assertions, but doesn't provide the graphical data to support them.

Quote:
One example method is to measure the ovaling present in an antique instrument, then combining that with
information about the ratio of tangential to radial shrinkage for the species of wood that the instrument is
made from. Assuming that the freshly reamed instrument had a round bore, then the more it has shrunk
the more oval its bore will be. If it is still round, then it either hasn't shrunk very much or it has been re-reamed.


I did try to use the ratios of max and min diameters to calculate the starting diameter on some flutes, but always ended up with numbers that made no sense or, at least, seemed impossible. But I think we now know why. My thread compression study showed that a side effect of the compression is pronounced ovality. So those parts of the flute at or near a tenon are going to give different results to those parts of the flute well away from a tenon. And do his torturous maths based on natural shrinkage hold up for artificially-produced compression?

Quote:
On the issue of those cracked ivory rings on wooden flutes, I agree that there are a lot of them. It is interesting
that they were placed there to prevent the thin and vulnerable wooden sockets from cracking, but invariably,
that thin, vulnerable wooden tube cracked the ivory supporting ring that was shrinking against it. It shows that
wood is not so delicate and easily crushed! :poke:


Indeed, making it all the more interesting that thread can do so much damage. But of course, it's not just thread, it's my Serial Strangler, the human owner who rewraps the thread tighter from time-to-time, giving the thread a fresh bite while the victim is already wounded.

I haven't looked into the shrinkage rates of ivory, but it's clearly faster than the shrinkage rates of wood. Not only do ivory rings crack, but the cracks on ivory heads always seem wider than the cracks on wooden heads. Not very scientific observation, I know, but....

And we know that wood resists crushing well, but doesn't resist splitting well (which is why we need rings). It would be interesting to know if ivory shares that characteristic.

Quote:
I also read recently (and this is confirmed in the New Langwill Index) that when Heinrich Grenser died in 1813,
his workshop was inventoried, and the contents included 7 lathes, a polishing machine, 120 turning bits, 12
thread cutters, 43 reamers for flutes, 48 reamers for oboes, 10 reamers for clarinets, 1 for basset-horn,
35 for bassoon 14 for serpent, and a further 86 unspecified reamers!


Yeah. Big business for way back then. And the French ditto - I remember reading how one French factory was producing flutes by steam! Whereas we know that English flute making was a much simpler affair. If you look at my images of the Rudall Carte factory:

http://www.mcgee-flutes.com/RC_Wshop1922.htm

We see quite a few lathes, but they are all treadle, and this in their 1922 catalogue! And we know from their factory records that the wooden flutes were made by outworkers, probably working from their homes. Unfortunately the loss of earlier workshop books makes it impossible to know how it was done back in the Rudall and Rose days. Ah, except perhaps for a few clues we get from trials at the Old Bailey:

http://www.mcgee-flutes.com/Rose%20vs%20Camp.htm

I think we have to be careful not to imagine our predecessors are like us, educated flute tragics obsessing over every last detail. I think most of them were essentially uneducated woodturners trying to earn a crust....


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Thu Feb 27, 2020 11:20 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 7:19 pm
Posts: 531
Location: Hood River, Oregon, USA
I think it is pretty clear from historical documents that earlier flute makers were a LOT more knowledgeable than today's
makers. I've been reading a translation of Quantz's book recently, and the chapters on "Of the Fingering or Application,
and the Gamut or Scale of the Flute" and "Of the Embouchure", are fascinating. They go a long way toward explaining
some of the alleged tuning anomalies you posted earlier, with no need to resort to theories of strangulation etc.

The interesting thing about the ivory bands that crack is that the wooden part of the socket that they wrap is typically
very thin, often on the order of only a couple of mm or so, which is only a fraction of the wall thickness of a tenon. So
this is a very delicate wooden tube compared to a tenon. Even a tube this thin-walled can overcome an ivory band which
is much thicker. It does suggest to look more closely at exactly how and why this happens.

It also reminds me of Claire Soubeyran's scientific study of tenon compression. Her results showed that the type of thread
used to wrap a tenon strongly influence the outcome. A thread that stretches and does not absorb water (such as waxed silk
thread) does not compress a tenon any more than cork does. However, a cotton thread that does not stretch and that expands
when it absorbs water, easily compresses a tenon.

In the case of socket reinforcement, the ivory band has no stretch/give, and is on the outside and hence subject to tension not
compression. I suspect that ivory, like wood, is much stronger under compression than tension.

The basic lessons I draw from this is (a) wrap your tenons with something that stretches enough to accommodate the
movement of the wood, and (b) reinforce your sockets with something that is strong under tension.

The fact that we have examples of thread wrapped antique flutes that remain relatively free of tenon damage shows that it is
possible to satisfy both of the above rules by using the right kind of thread and the right method for wrapping. But the tuning
of these flutes still have similar tuning issues to others, when compared to a 12 TET A=440 hz tuning standard.

In my opinion, the tuning anomalies mostly just reflect the fact that the wrong tuning standard has been selected to compare
the flute to, and no account has been made for the music that the flute was intended to play.


Top
 Profile  
Reply with quote  
 
 Post subject: Re: Rockstro
PostPosted: Fri Feb 28, 2020 11:27 pm 
Offline
User avatar

Joined: Sun Dec 12, 2004 4:12 pm
Posts: 2179
Location: Malua Bay, on the NSW Nature Coast
paddler wrote:
I think it is pretty clear from historical documents that earlier flute makers were a LOT more knowledgeable than today's makers. I've been reading a translation of Quantz's book recently, and the chapters on "Of the Fingering or Application,
and the Gamut or Scale of the Flute" and "Of the Embouchure", are fascinating. They go a long way toward explaining
some of the alleged tuning anomalies you posted earlier, with no need to resort to theories of strangulation etc.

Heh heh. "Alleged tuning anomalies"? "No need to resort to theories of strangulation"? Strangulation is proven and documented in my papers. Anyone wishing to deny strangulation would have to disprove it. And explain why when a strangled flute is unstrangled it gets better in tuning, note quality and performance terms.

Check out these magnifications of the first 70mm of a number of period flute bores. The tenons run for the first 28mm or so. So do the worst of the distortions. But note, if the distortions under the tenon are bad enough, eg in the case of the yellow "strangled boxwood" flute, the distortion can run a lot further down the bore.

Image

What other explanation do we have for this distortion?

Full story at: http://www.mcgee-flutes.com/wrap-survey.htm

We have to remember that Quantz's time was very different to the mass-produced world of Rudall & Rose, and the even more mass-produced world of Rudall & Carte, Boosey & Hawkes, etc. There were periods when few or even nobody at Rudall & Carte actually played flute. It was a job, not a passion.

And the 18th century flutes were very different. Most significantly, they only went down to D, and featured really prominent terminal bore flaring. Quantz argued against the C-foot at the time, for good reason - it severely weakened the low D. And they dealt with differing pitches intelligently, with corps de rechange, not the foolishness of one body having to cover A 430 to A 455! What were these guys thinking?

Quote:
In my opinion, the tuning anomalies mostly just reflect the fact that the wrong tuning standard has been selected to compare
the flute to, and no account has been made for the music that the flute was intended to play.

That was presumably in Rockstro and Ellis' minds when they measured the tuning of a Rudall Rose flute back in their day, and got results strikingly similar to what we so often see today:
Image

(Full story at: http://www.mcgee-flutes.com/RockstroAnalysesRRflute.htm)

Note they tried both Equal temperament and Meantone. What other tuning standard would you propose that would make sense of that? We can easily superimpose other tunings to test any theory.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 145 posts ]  Go to page Previous  1 ... 6, 7, 8, 9, 10  Next

All times are UTC - 6 hours


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group
[ Time : 0.132s | 11 Queries | GZIP : On ]
(dh)