Headjoint stopper design and materials

Irish Flute
1

In discussions with Tom Aebi, he told me that he had redesigned the stopper for his flutes, and that they had a big effect on the sound and response of the flute, and that he would send me one.

It arrived a few days ago. I don’t know if he thinks the design is proprietary, so I will just say that the obvious effect of the design is to greatly reduce the amount of space the cork occupies in the head joint (or increase the amount of air…). The old stopper occupied at least half the space between the end nearest the embouchure and the end of the head joint, whereas the new one occupies only a few millimetres all told.

My observations are that the response is better both between octaves, on rocking pedal motifs (BEdEBE, or BGdGBG), and on rolls and crans. The tone is more complex, noticeable everywhere, but for the first time I hear harmonics/overtones clearly in the second and third octaves, whereas before I found it hard to hear overtones in the high notes. On the whole, the response from different notes is more stable, so the low E which can be weak or muffled now blasts out like the low D-amazing considering that little hole. Finally, I think the flute is louder, but I’ll know after I play some tunes with my friend with Hamilton. I wrote him with my comments, and he replied that my comments agree with others who have also tried it.

Robert Bigio also makes custom stoppers out of various materials. (Just google his name and flute). I have one on order, but it hasn’t arrived yet. Dr. Bigio has some interesting links to those who have tested the effects of different materials and weights on perceptions of flute tone and response, but says cheerfully that he doesn’t really know why they work, just that they work. He uses a different approach than Tom Aebi, but the net effect is similar-much more air in the head joint, but in addition the crown has a hole in it.

So this is just my person’s experience, but I’d be interested to know if anyone can explain this, or has similar (or different!) experiences with stoppers.

Hugh

2

Well, I don’t have anything quite like your experience, but it sounds as though you have discovered something new, in regard to head joint cork.

I, for one, am listening, and thank you for sharing your experience.

:slight_smile:

3

Hi,
I don’t quite follow you on “increasing the amount of air” by having a thinner cork. The placement is the same from the middle of the embouchure hole. I think with Robert Bigio’s stopper he is counting on his 7mm thick stopper that is suspended on a O ring, will resonate through the crown that has the hole in it. Are you referring to the air on the other side of the stopper?
Thanks,
Jon

4

similar experience here, also received tom’s new stopper, few months ago: bigger more complex sound, louder, and greater response…
the first stopper was made out of delrin and the new stopper has a brass disc facing, like the lining of the head.
it makes a world of a difference…amazing what just a stopper can do!
was like having a different flute.

berti

5

I have one of Terry McGee’s flutes which has a thin stopper of some manmade material. Can be adjusted by means of turning end cap. Is is that sort of thin stopper you mean?

6

Interesting! I’ve been curious about Bigio and his experiments for a while, but have never gotten around to spending the money to try one.

I’m assuming from your description you mean a smaller head cork in your Aebi, Hugh? The bigger “air-vibration chamber” idea makes sense, but I never thought you could do that without changing the tuning fairly substantially (like what happens when you move the tuning cork).

Boehm flutes have metal discs such as Berti describes. Makes sense to not have some deadening material like the commonly-used cork exposed when you’re trying to boost resonance – it’d be like hanging a padded panel in a live room (which of course can be good and in fact necessary in a recording studio, but maybe not so much in a flute?).

7

I had some interesting stopper experiences some years ago: I used to have a blackwood Boehm head by Terry McGee, and I installed a Bigio stopper, which certaintly did give the flute a different feel and sound (more resonant and ringing). However, I ultimately wound up putting the original screw-cap and cork stopper assembly back in, and Jeff Weissman (Queens, NY) added a few ounces of weight to the assembly, which made the headjoint darker and more resistant. I also tried a Bigio stopper on my Copley & Boegli (although without the perforated end cap), but the effect, as I recall, wasn’t substantially different from the original set-up. I think it was a bit more free-blowing, whereas the original stopper (also delrin, held in place by O-rings, but a bit heavier and without a groove) made the flute a bit more resistant. I’d like to try it again, but I lost the new stopper in a move…
It’s interesting, if I simply remove the endcap, the flute plays differently than with it on (I prefer it on)–you can try this on lots of flutes; just unscrew or pull out the endcap (depending on design), leaving the cork/stopper in place. In fact, this seems to be how Robert Bigio stumbled upon his whole endcap/stopper redesign.

It’s all very bizarre, how a bit of weight, or a hole in the endcap, or a groove in the stopper face can have dramatic effect on the playability of a flute. And what works/sounds good for one flute may have quite the opposite effect on another.

Here’s an interesting article comparing the effect of different stopper weights and materials: http://www.larrykrantz.com/stopper.htm

8

Thanks, Tintin! While I’m reluctant to mess with the stoppers on my wooden flutes, that reminded me to have another look at the stopper on my Forbes … it’s Delrin with two O-rings, a double-O-ring version of one of the stoppers Symington describes.

Hmmm. The flute sure is loud and free-blowing!

9

Hey Hugh, :slight_smile:

The following is a picture of the stopper and cap from a Hoza wooden flute. Mark Hoza patterned his after Bigio’s and uses it with his permission.

I like the stopper fine, but I’m not sure about the end cap. I think the Delrin disk does increase the projection and response. However, sometimes I get a buzz in the endcap (could be a bit loose) and it drives me crazy. I’ve simply cut a disk of cork that I place against the back of the Delrin disk to dampen the vibrations.

I harden nealy all of my cork faces in my flutes by painting them with super-glue. This also increases the flutes projection.

All the Best!

10

I’ve done the superglue trick on some of the flutes and piccolos I’ve been doing up - though I can’t say I’ve noticed it make any significant tonal difference. I did it chiefly to seal them and make them harder when pushed against by a cleaning or adjusting rod. I’ve also done a couple that I filed down a 10 Euro cent coin for and stuck it on as a face plate - but again, I’m not sure I can hear any difference. That of course has nothing to do with any cavity behind the stopper or communication between that cavity and the outside. I’ve played flutes with no (or lost) crown caps - and can’t say I’ve noticed that make any difference either. Not so as one would say " Hey wow, this flute without a cap sounds so much…"

11

Jem - I’ve glued dimes on corks and like you, was simply not sure it made any difference…except once when the glue failed and it somehow angled itself sideways in the headjoint - that made a difference, but not in a good way.

I may try the superglue trick…because I can always cut off the cork tip if I don’t like it.

Eric

12

Skip Healy (on his Bb fifes) makes his stopper with a cork sleeve around a piece of wood (much like you would see on a tennon). I have often wondered why this is not the norm.

13

I would be concerned with a unlined head joint, that the wood may swell and crack the head. Delrin is pretty stable so should work. I am all for good old cork, especially after buying 1000 corks on eBay! :blush:

14

I experimented with cork thickness yesterday and cut a 3mm piece from the end of my flute’s cork to see what happens with a thin cork. I didn’t note any difference. Plays just as well as with the original cork which I put into the head piece again afterwards.

15

I’ll admit to being rather skeptical about the benifits of stoppers too, having done some experiments which seem to me to suggest there isn’t much criticality about them. I use a delrin stopper, wrapped with cork, and with a brass screw back to the cap to permit easy and fine adjustment. I’ve also used plain cork, cork with a brass face, cork with a silver face, and delrin with an O-ring seal. I’ve tried flat faced stoppers, hemispherical-faced stoppers, and faces with stepped holes in the surface. I’ve even drilled holes right through stoppers and found it amazing that it didn’t ruin the response as I expected it to! I think I have to concede the acousticians appear to be right - the stopper itself is of little significance, the important bit is the cavity formed between stopper and embouchure hole.

How can I be sure? I can’t. To be sure, you have to do double blind testing. Somebody other than the player has to load and adjust the stopper, and pass the flute to the tester, who therefore will not know which stopper is fitted. The tester passes the flute to the player, and collects the responses. If anyone can carry out this process and achieve repeatable results, they will have my full attention!

Terry

16

with all the above, would be an interesting experiment…any volunteers???

berti

17

If someone were to carry out the experiment, it would be interesting to have an audience as well, to answer the question can only the player hear a change, or does it affect the listener. Even one audient would be infinitely better than none. The audient can’t be the stopper loader, the tester or the player. Where do we find four individuals, only one of them having to have any skills at all?

Actually, if you can muster an audience, it’s good to know which ones have musical skills, to see if that determines how sensitive they are to the changes. Also good to make a good recording of the playing, to see if the player can hear any difference in the recording (assuming they could hear or feel a difference in the playing situation.

Terry

18

Put me down as one who thinks they can make a huge difference, at least on Boehm flutes and piccolos. Much of the difference is response - i.e. how it feels to the player. I’ve found that a heavier crown adds more depth and resistance. If it’s too heavy, it can deaden the sound. A light-weight crown aids responsiveness, and decreases resistance. But a crown that’s too light can prevent you from pushing the sound, if that’s the way you like to play. I’ve found that each headjoint responds differently to various crown sizes and types, so there are no pat answers. Plus, players are looking for different qualities. So while I see definite differences, I’ve found no formulas.

I recently asked the maker of my picc headjoint to send me a lighter weight crown, to see if it would decrease resistance in the third octave. He sent me three crowns, all identical sizes, but different woods. Two were lighter-weight blackwood, and one was coccus. I ended up trading for the lighter blackwood crown, and I’m pleased as punch. I sacrificed virtually nothing in tone quality, but the high notes respond with less work.

Dana

19

To follow on from Terry’s comments.

Interestingly, humans are relatively insensitive at detecting changes in loudness. So in a blind test where many listeners hear exactly the same sound sample, but one is 1-2 decibel louder than the other (the engineer just turns up the gain on the preamplifier to generate the louder sound from the same sample), most listeners will report that the sounds are the same loudness. Nevertheless, if you ask them which sound they prefer, most listeners, trained or untrained, will prefer the louder sample, but will describe the louder sample as “richer, more complex, more detailed”, rather than say, “the sound is the same, but this one is louder than that one”.

This points out a way that Berti and my impressions, and Terry’s measurements with different corks (eg corks don’t make an obvious difference to the sound) could both be true. If Tom’s cork makes the flute louder, but not much louder, our brains will pay less attention to the difference in loudness, and instead ascribe the differences to changes in the complexity of the sound. If this is what is happening, Terry wouldn’t measure any obvious difference in the sound spectrum with different corks.

The difficulty with a live player is that there will always be differences in loudness that will be enough to make the comparison between corks futile, I predict.

If there actually is a difference in the sound produced by different stoppers, I’d vote for a good recording of a flute player playing the same flute with different stoppers blind, and followed by analysis of the sound spectrum. The claims I would make about the new stopper vs the old stopper (more harmonics in second octave), louder E relative to the D, would show up in an instant. There’s lots of arguments about this, but my position is that if a difference in sound can be heard, it can be measured.

If one does do a listening test, the way that works the best for difference testing is to give listeners that chance to hear sample A, sample B, and and an unknown, and ask them to say whether the unknown is A or B. (In this case, A and B would be different stoppers, and the unknown would be one of these stoppers). The player that generates the sound samples still has to be ignorant about which stopper she is using, so there isn’t unconscious bias towards making a better sound with the “right” stopper. The listeners are allowed to listen to A, B and the unknown as often and as long as they like before making the identification of the unknown. The faster the listener can switch between the samples, the more likely they are to be able to identify the unknown. The listener’s ability to remember the sound of A, B and the unknown so they can make a decision about the identity of the unknown vanishes if the interval between hearing A,B, and the unknown is longer than 30 seconds. If the listener has to wait for the corks to be switched, the player to find their embouchure again, and then say whether the sound they are hearing is A or B, there is effectively zero chance that they will find a difference. So I think this has to be a test done on tape.

Having said all that, I’d bet Terry could measure a difference in the sound spectrum with Tom’s new “cork” versus his old one. The design is enough different from every other stopper I have seen that Terry is unlikely to have tried one like it. FWIW, I didn’t expect the new stopper to make any difference, and was astonished when I detected a difference that is not at all subtle.

I bought myself a nice condenser microphone, but so far have been completely stymied setting up the interface that connects the mic to the computer. When I figure it out, I’ll see if I can produce anything convincing. My guess is that hearing the difference between crispness of my rolls on E with old and new stopper would be easily detectable, and that there is a chance of hearing the change in relative loudness between the E and D with the two corks.

Course, such a test won’t be blind, so sceptics could correctly discount such a result if one was obtained, by arguing I was “trying harder” with the new cork as a result of bias conscious, or unconscious.

Cheers,
Hugh

20

Hmm, what if the difference in sound you’ve discovered Hugh, is only perceiveable to the player, not the listener, and can’t be measured? Maybe it’s only detectable to the player’s ears? The human auditory interface is kind of a sophisticated system in itself, along with the rest of the package-it’s hard to explain a lot about human beings. Make any sense? Probably not! :laughing: