I have one of Geoffrey Ellis' ebonite Pratten-style flutes, and really love it. Part of my interest in it was the fragility of wood--where I live there are wild fluctuations in temperature and humidity during the year. It's light and feels very lively and responsive, and it's extremely low maintenance.

It is hard to beat Delrin in many ways. I have two Delrin flutes, an M&E and Walt Sweet "Shannon," and while I don't like either one nearly as much as the Ellis, they were cheap and are easy to play and sound good. They both have a slightly "damped" quality compared to the Ellis, but I doubt listeners can hear that.

I'm intrigued by the resonance you get from ebonite. More noticeable than wood or Delrin. I get why Rockstro called it a superior material Just had this in an e-mail from a customer who bought an Essential flute from ebonite:

" I cannot imagine a more beautiful coloration of ebonite! But as you know, and have said, the real beauty is in its exquisite timbre. Perhaps the inherent elasticity of the natural rubber, and the homogeneity of the material, give it especially resonant qualities? In any event, it caused my music room to vibrate in sympathetic resonance in a way that I have
previously never experienced. "

Every time I pick up an ebonite flute I have this experience and it makes me wonder about the nature of the material. I don't know that it's a difference that is obvious to an audience, but it's remarkable "under the ear" and under the fingers.

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Geoffrey Ellis Flutes

My experience with ebonite comes from the clarinet world, but it seems to me that the bore of an ebonite clarinet mouthpiece is much smoother than the bore of a flute made of ABW. Is it possible that the perceived difference in sound comes from the material's smoothness, rather than the material itself?

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"Wimble click crumblechaw beloo. It is beautiful, is it not? I make up words like this all the time... They cannot be translated." The New York Trilogy, Paul Auster

Achieving smoothness within an ebonite bore is actually quite tricky, especially if that bore is not cylindrical all the way through. I've had to develop a lot of technique in how I drill and ream it, involving multi-stage processes (some of which I'm even a bit secretive about!). The tricky part of drilling and reaming ebonite is that the heat from friction softens ebonite and makes it cut rough (micro-tearing of the surface), in much the same way that wood will do. A lot of the rather involved techniques I've perfected greatly reduce this, but a certain amount of sanding and polishing of the bore is still sometimes needed.

I think the smoother the bore is, the more responsive the flute, generally speaking, so I think that is undoubtedly part of the equation. However, in the case of ebonite there is something going on with the material itself beyond just how much polish you can achieve inside. Because I finish many of my wooden flute bores with clear marine epoxy, I'm able to give them a glass-like smoothness. I've achieved similar results using a polymerized linseed oil in the bore as well. In both cases (super smooth bores) the flutes did not sound/feel the same as an ebonite flute. The ebonite simply behaves differently. And this is not a "better" or "worse" type of evaluation of course, because the things I like about ebonite may not appeal to another player. It has a liveliness to it, and what I call a warmth and resonance, but to someone else that might be "buzzy" or "too bright". Your mileage may vary.

The thinner the ebonite, the more I notice it. On my Essential Flutes, the walls are only about 3mm thick, and you can really feel the resonance. I just made a shakuhachi flute from ebonite, and while I can perceive some of that same quality, it's not nearly as obvious when the walls are 7+mm thick.

But my own experience so far, having compared wood and ebonite side by side on a lot of different flutes, and I'm totally convinced that it is unique in it's character as a result of what it is made of.

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Geoffrey Ellis Flutes

Thanks for your detailed explanation, Geoffrey Is it possible to achieve the same wall thickness (~3mm) with wood? I would expect that the thinner the walls are, the more resonant the instrument feels to the player, as you seem to suggest.

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"Wimble click crumblechaw beloo. It is beautiful, is it not? I make up words like this all the time... They cannot be translated." The New York Trilogy, Paul Auster

Definitely. It all depends on the design of the flute. A Pratten flute (conical bore) such as many players utilize in this community, has a wall thickness of about 4.5mm. My Essential Flute is about 3mm, regardless of material. When I make an Indian bansuri from wood, the walls are 1.5mm thick (I have not yet made one of these from ebonite but I mean to try it). With thinner walls the player definitely feels the resonance more. I don't think an audience listening to the flute will perceive this resonance, however. It's all for the player. But speaking personally, I love this feedback loop. I like to feel the sound in my fingertips and in my face. It has an objective effect on my playing, I believe. My friend Ron Korb humorously described this feedback loop as "The Ego Effect". He said that a really good wooden headjoint (for example) will give the player a strong "under the ear" experience that makes them feel like they are a flute god!

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Geoffrey Ellis Flutes

I was just practicing with one of my Delrin flutes, because it's quieter, and it does have a less lively feel and is less fun to play. The delrin flute I was playing--a heavy M&E can be made to sound good but feels more like driving a heavily laden truck

This may not have any bearing on sound but Ebonite is an odd material thermally. It doesn't "clog" nearly as often as delrin. I'm not sure why this should be but here is something peculiar about it thermally.

I posted this in my blog about ebonite, but I think I got it from Hammy Hamilton's site? I think my memory is accurate on that...

From Rockstro on ebonite:

" -Firstly, then in the matter of endurance it may be pronounced perfect for it is practicably indestructible.


-Secondly, as it is absolutely non-absorbent of moisture no change in the dimensions of the tube ever occurs, and a metal head-ling is unnecessary.


- Thirdly, an ebonite flute invariably improves by judicious use.


- Fourthly, this substance possesses just the amount of rigidity necessary for the retention of the enclosed air-column in its proper shape and dimensions, while its own vibrations sympathize so readily with those of the air within, that the sound is produced with as little expenditure of the breath as on a metal flute.

- Fifthly, this material is so bad a conductor of heat that ebonite flutes are far less affected than any others, in their pitch, by alteration of temperature.


-Sixthly, its appearance excels that of the finest ebony, and it generally retains its original lustre with very little attention, though sometimes it loses its extreme blackness.
"

Given Rockstro's somewhat controversial reputation, I wouldn't necessarily take this as the final word . I don't agree with the indestructible part, for sure. And I don't know about it improving with use either because I haven't kept an ebonite flute on hand long enough to judge. As to sympathetic resonance, dimensional stability and heat conduction I think he is accurate.

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Geoffrey Ellis Flutes

With regard to consumer preference for wood over synthetic materials, there is also an availability issue when you get into the realm of modern-made "Irish" flutes with keys.

I know M&E makes a keyed flute in polymer, but very few other keyed flutes are available in anything other than traditional hardwoods. Especially in 8-keyed versions. I think this lends a certain status to wood as a flute material, regardless of the fact that you're paying mostly for the labor-intensive keywork and not the raw materials (unless it's something like Cocus). It's difficult to avoid the perception that wood is the superior flute material, when it's almost exclusively used for the most expensive "Irish" flutes in new production.

I don't know why more keyed flutes aren't made in synthetic materials. If it isn't a weight issue (and it could be with Delrin?), maybe it's just a Catch-22 situation. Makers won't bother offering them if nobody's buying, and nobody's buying because nobody is offering them.

I keep thinking about getting a keyed flute I have an old anonymous keyed flute that's not very good, but I keep thinking about getting a good one. They're a pretty big investment and if I worry about cracking in a keyless...

I think Dave Copely makes a keyed delrin flute. I haven't tried one of his but they get good reviews

I just checked--he makes a 6 keyed or a four keyed flute in delrin

Dave Copley will make up to an 8 key in Delrin...I have one. I like ebonite, I like Delrin, I even like wood...it all depends on the maker. Dave Copley, Francois Baubet, etc...a good maker will make a good flute that to met at least doesn't seem squishy at all.

Whatever floats your boat as far as I am concerned. I don't love Carbony flutes. I was trying them at the KC Irish Fest when he was selling what I would consider significantly subpar flutes. They're better now, but many sound squishy to me and I don't like the aesthetics at all.

YMMV,

Eric

Your way of describing the influence of ebonite on the way the flute feels is akin to what one says about the natural ebony wood, no? Italian flute maker Fabio di Natale proposes his flutes in what he calls synthetic ebony (http://www.fabiodinatale.com/en/materiali.html). I wonder if it's the same thing as ebonite. He claims it has a density of 1,3 g/cm3, while ebonite is 1,1 to 1,2 according to Wikipedia.

I don't think the sythetic ebony is any relation to ebonite. He describes it as being made with a resin of some kind. It might be a mix of wood dust and resin? Just guessing. Ebonite is a mixture of rubber sap, linseed oil and sulfur, which is then baked in an oven causing it to "vulcanize"--to turn into hard rubber. It's made of natural ingredients that are transformed using heat.

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Geoffrey Ellis Flutes

Thank you for the explanation. Indeed, I see now that it can't be the same thing: his synthetic ebony flutes are 30% cheaper that his wooden flutes. However, it seems that natural rubber sap can be replaced by a synthetic rubber (Styrene butadiene rubber, for exemple) and then vulcanized in the same mixture. Such synthetic "ebonites" seem to be used in the industry. There's no guarantee that the acoustic properties would be the same though. It would be exciting to have a material that is cheap and at the same time acoustically "interesting".