Intonation again

[MTGuru]

I wonder why everyone mentions the cork position when someone's talking about tuning of individual notes. Moving the cork won't affect the tuning of the low register at all

Sure it will, at least indirectly. If you have your slide set for your tuning pitch and good octaves but the cork is wrong, the bore length is simply wrong for the hole layout, including in the lower register. Which can produce bad note-to-note intonation, and tone/response issues as Casey describes.

[kkrell]

Gabriel, I'm using this sort of non-flutemaker's logic: IMO, there is a relationship between cork position, slide position, and response. Response (how the flute blows) is going to affect the player's ability to control the instrument, and thus the intonation (assuming a well-designed, functioning flute). And yes, cork positions can vary, and sometimes around 19mm works OK.

[Gabriel]

It is a common error to think that the space from cork face to embouchure axis contributes to the sounding length of the flute. It does not. Try and set your cork at a ridiculously far point, say 40mm, and play low D. It's still low D, not C# (low C#-C hole distance usually about 40mm, so sounding length of embouchure axis to low C#, which gives D, plus 40mm = sounding length for C#). Draw out the slide 40mm and you have C#. Same vice versa, set cork to (embouchure width)/2 and play D: still D, not something like Eb. Saw barrel off: Eb. Try it, it's like that (I'm not responsible for divided barrels). Internal tuning within one register doesn't change at all. Performance does, though. The higher register goes a bit sharp relative to the lower register the farther the cork is at the embouchure, and vice versa. At 40mm, the second register is quite flat. But that is the one and only influence the cork has on tuning. Individual notes can NOT be tuned with the cork.

All this is nicely summarized (and explained with complicated equations) in Otto Steinkopf's "Zur Akustik der Blasinstrumente". I'm sure there's a similar book written in english.

Kevin, of course you're right. A flute that works not very well for me will likely not play in tune as well as a flute that works great for me, as I feel uncomfy on it and don't put much effort into it. Moving the cork can change response (performance, that's how I call it), thus changing the flute to one that works better for me, and voila, tuning better as well. However, still, internal tuning is not changed by the cork. If F# is horribly flat relatively to its neighbors G and E, the cork can't be blamed for that. Hole size, position and undercutting can.

[kkrell]

Gabriel, thanks for adding that last paragraph when you revised. Now I think I can agree with you

In a flute or a whistle, the player adjusts intonation with their embouchure, slide position, and supporting air column (breath). Given a reasonably well-tuned and setup instrument, we depend on our ears to target the notes to where we want them. Mess with that, by having improper setup, leaks, foreign objects in the bore, stupid hole positions, or a badly cut embouchure hole, and it makes considerable work to play satisfactorily in tune.

Performance/response characteristics affect the player, who is going to have difficulty dialing in the notes reliably. Such struggles could make the player overblow, underblow, roll in, roll out, and screw up their embouchure to the point of tone and/or intonation suffering horribly. I think we usually do an amazing job considering all the usual little adjustments to be made during playing, but you don't get any improvement over time when the instrument won't make any sense. I think once Jumbuk gets his flute back to a proper and reliable setup, he's going to finally, and probably quickly, develop that improvement and general consistency that makes flute playing and practice a rewarding activity.

[MTGuru]

It is a common error to think that the space from cork face to embouchure axis contributes to the sounding length of the flute. It does not.

Interesting ... Thanks for the explanation, Gabriel. It seems very counterintuitive, but I'm always willing to learn something new. I have to think/read more about this (vielleicht wäre das Steinkopf-buch mit meinem Schuldeutsch lesbar).

As a Gedankenexperiment, if the distance from embouchure axis to bell determines the acoustic length ... What would happen if you could extend the distance to the cork to, say, 1 meter? Apart from performance, and ignoring the octave registers, would the intonation of the fundamental register be unaffected?

[Doug_Tipple]

The question "What is an ideal flute scale?" is more complicated than it may first appear, and I don't pretend to have many definitive answers. A lot of people have thought about this question over the years, and flute companies seem to be continually developing "new scales". We recently had a thread that dealt with modern revisions to the Cooper's scale, which I think is relevant to this discussion.viewtopic.php?f=2&t=81585

As an aside, I used to tune my pvc Irish flutes by ear, ostensibly close to Just Intonation. However, I now tune the flutes with a tuner to equal temperment, even though some of the intervals sound a little off, just as they do on a well-tuned piano. I have stopped getting the comments about my flutes being off-pitch by those who play in front of a tuner, and professional musicians seem to accept the equal-tempered scale, while not perfect, as being acceptable.

[jemtheflute]

I'm sure Steffen can respond to MTGuru's Q better, but here goes on my understanding of it. The upstream space in a flute, from embouchure to stopper face, acts as a Helmholtz resonator, not as part of the open-ended-tube-defined sounding length. This may be a very bad analogy, but it is kind of like a spring in the upstream cavity off which the to-ing and fro-ing of the wave in the main air-column bounces. This is why it affects tone production/response in the different registers differently and influences octave/register tuning. If you massively extend the stopped upstream tube, you still have a Helmholtz resonator (with a much larger volume), not an extension of the sounding length. Precisely how that works I don't know, either from empirical experience or in theory (I couldn't begin to do the maths). Open the stopped end, though, and all bets are off - you have two flute tubes driven by the same energy input and the wave-forms butt-ending each other. Don't ask me what happens, 'cos I don't know! (However, as I'm in the process of making a batch of piccolos, I may be in a position to try in a few days.)

I've certainly held forth on C&F in the past about the fallacy of believing tinkering with the stopper can try to address intonation issues such as a sharp A, flat low D or whatever.

I've also (more recently) written about modifying embouchure technique in a way the OP may find helpful. The faults he describes with his intonation are stereotypically those experienced by a modern Bohm flute specialist on casually picking up a simple system flute, often leading them erroneously to declare the flute to be out of tune; beginners with undeveloped embouchures typically experience similar issues. See these old posts/threads: viewtopic.php?f=2&t=80040&p=1002785&hil ... n#p1002785 and also viewtopic.php?f=2&t=79917&p=1001479&hil ... n#p1001479 (there's a bit about stopper position adjustment in this second one, too). I think both the OPs of those threads will vouch for what they achieved from working at following that advice. This one may help too: viewtopic.php?f=2&t=77666&p=983089&hili ... wn#p983089.

[Feadoggie]

Interesting thread. This paper on stopper placement might be interesting reading for some as well.

Feadoggie

[MTGuru]

The upstream space in a flute, from embouchure to stopper face, acts as a Helmholtz resonator, not as part of the open-ended-tube-defined sounding length.

Yes, that occurred to me as the explanation: a Helmholtz resonator damping the air reed, affecting mode-locking and response without changing the acoustic length.

As the Helmholtz volume increases, the Helmholtz frequency approaches zero, effectively non-resonant (I think). Opening the cork end completely creates an infinite Helmholtz space - the entire atmosphere - at which point the open-pipe resonant behavior of the upstream tube takes over.

Seems to me I've seen examples of flutes (SE Asian?) with a central embouchure hole and the tube extending on either side. Will have to check.

I also want to think about this in whistle terms, vis-à-vis the cavity-fill putty tweak.

This paper on stopper placement might be interesting reading for some as well.

Thanks! I'll read that.

[jemtheflute]

I'd read Feadoggie's linked article before - probably partly why I was able to make my half-baked post above . Having browsed it again, they seem to suggest that in fact the Helmholtz effect in the stopped end is over-ridden by the effects of the upstream space as a stopped tube beyond a certain extension of it, though they don't appear to say what the switch-over point is. And my spring analogy above was an oversimplification to say the least - as MTGuru says, the embouchure chimney is also part of the resonator and the oscillation of the air-reed which is the tone generator is affected by the whole Helmholtz complex as well as the behaviour of the main tube's wave-form. The paper certainly seems to offer an explanation for the empirically observation that having the stopper further back enhances the low register tone (by favouring certain harmonic content) whilst bringing it forward aids the higher registers, as well as for its position's role in octave tuning. Of course, as always with flutes (!), we have to adopt a compromise in that the optimum position for one kind of tone may not be the optimum for octave tuning.....

Just a note for the avoidance of confusion for anyone reading that article: the "standard" position for the stopper at 17-17.5mm from the embouchure centre to which it refers is for Bohm flutes, not cylinder headed, conoid bored ones.

[Feadoggie]

I also want to think about this in whistle terms, vis-à-vis the cavity-fill putty tweak.

Yep, me too. I have no conclusions myself as yet. I do suspect thoughts related to this may be behind the concave face on the plugs used by a small number of whistle makers like Glenn Schultz.

Feadoggie

[MTGuru]

Seems to me I've seen examples of flutes (SE Asian?) with a central embouchure hole and the tube extending on either side. Will have to check.

I found one reference so far: H. Macaulay Fitzgibbon, The Story of the Flute (1914).

Most curious of all is the Hwang-Chong-Tsche or Ch-ih, a transverse flute, with a lateral mouth-hole in the middle of the tube and finger-holes on each side of the mouth-hole. The number of finger-holes sometimes amounts to ten or more. This instrument, which was described by the French Jesuit, Pere Amiot, in 1780, is very possibly the earliest known side-blown flute. Prince Tsai-yu (1596) says it dates from c. 2200 B.C. In its original form it was open at both ends, but is now usually plugged in the middle, and additional holes are added at one end in substitution for those beyond the plug. The holes on the original form were placed at unequal distances from each end, and were uncovered alternately to produce the scale.

http://www.archive.org/details/storyofflute1914fitz

[MTGuru]

So I spent an hour this afternoon with my Tipple D, some corks, and tape, using the flute sections as test-tubes, treating various finger holes as embouchure holes. And so far I've concluded that:

1. The behavior of a tube on either side of the embouchure, and the transitions between closed-tube, open tube, and Helmholtz resonance are ... complex.

2. There are probably healthier ways to spend an hour than experimenting with flutes.

[Akiba]

2. There are probably healthier ways to spend an hour than experimenting with flutes.

I often end up feeling this way (the little barstards)...

[talasiga]

The cork position on my flutes is important for best tone production first. If the cork is adjusted wrong, then the bottom D maybe doesn't play in as well, causing all sorts of mischief to the intonation there and elsewhere. This 23-24mm is the "factory setting". Outside of those parameters and the player is on his or her own. This is why.

interesting.
yes, just picking up one of my small concert bansuri and changing cork position I found the pitch of the notes in the lowest octave changed up or or down. Also pushed further up into the head some notes got "airy".

Sillily I forgot to mentally mark where the original cork posi had been so I had to reset it on the following basis
with mid octave octave XXX XXX 2 cents higher than the ET fifth for low octave XXX OOO.