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!
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!