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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 4:52 pm 
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jim stone wrote:
Once, long ago, we got into a brawl about pinky placement that resulted in the board's being shut down for two days.

Seems a bit extreme; I don't remember it. A locked topic, perhaps?

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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 5:16 pm 
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Nanohedron wrote:
... If we can't avoid a tone of hostility (deny all you like; that's how it looks), the thread will have to see an unfortunate end...


Well, I, for one, hope this conversation can continue, as I find it fascinating. I would also like to state that nothing I have read so far, has come close to what I would consider inappropriate. Most meaningful discussion will involve disagreement and a wave of opposing ideas, often expressed with frustration, until an understanding occurs.


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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 5:43 pm 
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D Mc wrote:
Well, I, for one, hope this conversation can continue, as I find it fascinating.

As do I, on both counts.

D Mc wrote:
I would also like to state that nothing I have read so far, has come close to what I would consider inappropriate.

I happen to know that not everyone shares your opinion, and from an Admin standpoint, that difference becomes a concern.

D Mc wrote:
Most meaningful discussion will involve disagreement and a wave of opposing ideas, often expressed with frustration, until an understanding occurs.

Disagreement and frustration need not rule the tone of one's speech. What I am counseling is calmer exchange. We're all capable of it.

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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 6:07 pm 
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Nanohedron wrote:
jim stone wrote:
Once, long ago, we got into a brawl about pinky placement that resulted in the board's being shut down for two days.

Seems a bit extreme; I don't remember it. A locked topic, perhaps?


Long, long ago, when there was one board for whistles and flutes. It was, I think, the first time we really went off the rails. It was impressive. We hadn't evolved the procedures we now take for granted and the board, not quite knowing what else to do, shut down. I trust everybody sees the silliness of bringing together the few souls who care about pinky placement and having them fight with each other.


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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 6:11 pm 
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I remember the one-forum-fits-all epoch, but it was close to the tail end of it, so that episode was probably before I joined up. That's something you wouldn't forget.

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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 7:11 pm 
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If people are offended by the content of this thread then I think it is better for it to be locked.


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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 8:18 pm 
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I still wake in the night, screaming, Nano. A few of us remember what these boards were once like, and how a bit of snarkiness, tolerated, devolves into something primal. We've really have become something fine, the board a lot of people longed for back in the day. Immensely interesting and helpful. IMO, patience is very helpful here, and the occasional personal swipe is a luxury we cannot afford. My two cents. Paddler, I really like reading your posts.


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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 9:56 pm 
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Does anyone have any explanation for the following apparent contradictions?

1. Tenon compression, which causes bore restrictions in all known cases, causes the bore underneath the tenon in these flutes to enlarge rather than restrict? What physical process could possibly cause this?

2. Why does this not occur on the head tenons, even in these flutes?

3. There is a claim that bore perturbations, in the form of chambers at a tenon, surely must have an insignificant effect on flute tuning. But then we also see the same person claim that bore perturbations, of similar size, caused by thread compression at the same tenon, cause such significant detrimental effects on tuning that they should be considered a serious design flaw? Why wouldn't bore perturbations of a certain size at the same location in a flute bore have an effect, or not have an effect, regardless of what caused them?

4. A related question. Why would one believe that chambers in a bore have no acoustic effect, but that restrictions in a bore have a significant acoustic effect? What physics underlies these claims?

5. How can one claim to definitively know that tenon compression has taken place in a flute, simply by looking at its bore profile, while at the same time claim that chambering has not taken place, when looking at a bore profile that contains chambers? If it is necessary to know the original datum line in order to make any claims about how accurately the existing bore profile represents that of the flute in its original state, then why does this argument not apply equally to claims of tenon compression as well as chambering?

6. If chambers in the bore of 1 mm are insignificant to flute tuning, why do the bore chambers left by tuning slides that are pulled wide open affect tuning? Tuning slide wall thickness is generally well under 0.5 mm, and the amount of slide opening is less than the length of a tenon? Players frequently pay good money to have a new, longer, modern head made for an antique flute rather than just open the tuning slide further on the existing head? Why would they waste their money if this has no effect?


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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 10:35 pm 
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I think that this does a good job of distilling the original argument into some easy to address bullet points and putting us back on track regarding the OP.

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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 10:59 pm 
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tstermitz wrote:
As far as I can tell, we don't have any explanation of WHY there are expansions either from acoustics or artistics other than it seem typical of R&R flutes.
To take the conversation forward, I think it would be important to have SOME idea, or maybe just some postulated ideas about the acoustic effect. Intonation? Power? Certain notes? Certain registers?
I


I think this is the question pointed to in the OP. It's of interest that Rockstro made reference to chambering, implying that there was a purpose behind it to enhance performance. Paddler's speculations about possible enhancement to third octave tuning seems like a worthwhile springboard for speculation, since these flutes would have been expected to play well in the third octave, and engineering a flute to behave a certain way in the third octave is a tricky business and probably involves a bit of voodoo :-). I've never made the attempt because it gets complicated quickly unless you have some skill with computer modeling. Regardless of Rocksto's credibility as an observer (and I know almost nothing about him--he might be a complete scallyway, but that's not the point), it is interesting that he made the reference at all, and that there is data at hand that seems to reflect that he was not talking out of his hat (at least not completely). None of this is to say that the chambering worked or didn't work as intended, but I find it interesting that the phenomena repeats on all the R&R flutes. Obviously I find paddler's interpretation of the data and his logic to be credible and I would be slow to dismiss it.

Again, these cavities in the bore are obviously there--they do exist. We can see them, however subtle they may be. The introduction of cavities in bores is a flute-making technique that has been used both historically and in contemporary flute making of various types. This doesn't mean it's common practice and probably not something a lot of makers of conical bore flutes have ever bothered much with, but that doesn't mean that therefore it's imaginary. Asian flute makers historical and modern have used it, and I'm guessing lots of flute makers from many cultures have messed around with constrictions and cavities in flute bores. Tomorrow I'll snap a photo of the mandrel I use to cast the bore of the optimized xiao that Yang Lan developed. This will bring new meaning to "chambering" :-)

To me, it seems pretty obvious that something is up with the R&R bores. Whether it achieved it's intention in the design is another question.

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 Post subject: Re: Rockstro
PostPosted: Fri Feb 21, 2020 11:35 pm 
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On the question of what acoustic effect these chambers have, the simplest, and most accurate, way to answer this question would be for an owner of a Rudall and Rose flute that exhibits this flaring pattern in the bore at the end of the middle and lower tenons, to take some blu tack, or other modeling putty, temporarily add a thin layer to the inside of the end of the two tenons in question, (for no more than 1cm of bore length and less than 1mm thick), and then try to play all of the flute's notes using all the available cross fingerings from R&R fingering charts. That way you can see if filling these chambers deteriorates the performance of any of the notes. If it does, then the chambers help those notes. A back of the envelope calculation of the frequency of those notes and their harmonics would then let you see which frequencies have pressure or flow nodes that fall anywhere close to the locations of the chambers. They would be the ones that were likely targeted by the chambering.

This test would have to include all of the third octave notes. If some notes speak better without the chambers filled, then I think this is clear evidence that the chambers have a beneficial effect on the flute's performance. If the flute plays the same regardless of the chambers being open or filled, then I think it is reasonable to assume that these chambers were produced by some other process and for non-acoustic reasons. Then we might consider what manufacturing processes might cause them. I have some candidates in mind for this line of thinking.

This approach is far more meaningful than trying to make reamers and test the effect of chambering on flutes with a different bore profile, a different number of keys, different fingering patterns and no targeted third octave tuning. Doing so changes so many parameters that it would not be a meaningful experiment. Using an existing R&R flute allows one to hold all other variables constant while varying only the one in question, which is important for it to be a valid scientific experiment.

Anyone out there have an R&R flute and some blu tack?


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 Post subject: Re: Rockstro
PostPosted: Sat Feb 22, 2020 3:55 am 
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paddler wrote:
to take some blu tack, or other modeling putty, temporarily add a thin layer to the inside of the end of the two tenons in question, (for no more than 1cm of bore length and less than 1mm thick)

Rolled plastic sheet is probably easier to manipulate, and Plasticine also better if you need a putty-like material that shapes better than Blu Tack; I've used both (not Blu Tack, which is too elastic) to tune whistles and recorders depending on whether I wanted a fine all-round perturbation or a simple lump.

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 Post subject: Re: Rockstro
PostPosted: Sat Feb 22, 2020 6:20 am 
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Woah, the bushfires in New South Wales appear to have nothing on the fires raging in a popular Irish Flute forum!

Now there's no way I can comment on a fraction of the above (I'm about to head to bed!). So I'll pick a point at a whim.

I'd said (of Rockstro):
"Fourthly, the concept of "chambering" is the sole invention of a known and proven liar. Why should we pay him any heed when all his other assertions have been thoroughly debunked? See Welch, for example."

To which Paddler responded:
"Wrong! Several people on this thread have stated that they have used chambering themselves. I have also used it myself. It is well documented in books and articles on flute making, and pipe making."

My point stands. Rockstro is the only period source that mentions "chambering". It's a throw-away line, and the term "chambering" doesn't even make it to his own Index. It is under-defined - we don't even know if he means a chamber in the caving sense of a "cavity larger than its upstream opening", or simply an "extension of a certain diameter for further than a straight taper would have implied". He certainly makes no reference to back reaming, or association with tenons.

Now, I've had a quick whip through of all my other period and more recent books on flutes - not one mentions chambering in its Index. A search on-line for "flute chambering" finds nothing apposite.

So, I have to challenge Paddler's assertion: "It is well documented in books and articles on flute making". Let us flush out these references and see if they speak to us....


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 Post subject: Re: Rockstro
PostPosted: Sat Feb 22, 2020 6:27 am 
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Oh, and one more observation. Rather than go to any physical trouble, why not first do some computer modelling of the differences between say the Rudall bore in question and one or more assumptions of what it might/should have looked like?

Tunborough, I notice you are maintaining a low profile. A healthy instinct for self preservation at work?


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 Post subject: Re: Rockstro
PostPosted: Sat Feb 22, 2020 8:27 am 
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You may want to have a chat to Craig Fisher and familiarise yourself with his work on variations in the bores of union/uillean pipes.

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