Why cocus?

[jim stone]

Whether the wood is vibrating itself and radiating sound (as in a guitar) on a flute is open to question. An interesting experiment would be to carefully wrap a flute with some sound deadening type fabric (except around the fingerholes and embouchure) and see what difference this makes to the tone, if any.

I suspect most of the significant differences to the tone between woods has to do with the boundary layer (air/wood interface) where most of the frictional forces on the sound vibrations occur. Differences in the woods' microtextures, pore spacing, degree of finish, etc. This is directly observable before and just after a flute's bore is oiled, which changes these parameters, if temporarily.

Just to be clear, there are two ways the vibrating wood might affect sound--we've mentioned them both in this thread. First, as you suggest it might radiate sound (as in a guitar). Call this the Radiating Account. Second, the vibrating wood might affect sound by affecting the
vibrating column of air in the flute. Call this the Column Account. Of course both might happen at once.

The first experiment you mention really sounds interesting, since if either of these ways is implicated in the flute's sound,
and we could stop or curtail the vibrations of the wood, if this altered the quality of sound it would be good evidence
that the wood's vibrating is making a difference some way or other.

If it made no difference to the flute's sound, then I think that would rule out the radiating account, since the wrapping would stifle radiation. There would remain the possibility that the flute is vibrating, though, just not radiating,
so we would need to be sure we are really curtailing vibration, not just radiation, to rule out the column account.

I agree that the sound change after oiling supports your interesting hypothesis that differences to the tone between woods has to do with the boundary layer (air/wood interface) where most of the frictional forces on the sound vibrations occur. But maybe it isn't decisive, since the oil may, by absorbing vibration, make a difference to how the wood
vibrates.

What would be interesting would be to line the bores of wooden flutes with a thin layer of delrin, say,
and see if different flute wood containers still
lend a different tonal quality to the flutes. If not, it would tend to confirm your hypothesis. If so, it would suggest
the vibrational properties of the underlying wood is making a difference.

One thing I do suspect, though this can be no more than a suggestion, is that, with silver lined head joints,
the underlying wood (blackwood or boxwood, for instance) makes a difference to the sound the head joint produces.
This perhaps provides some reason to think the vibrational features of flute woods can make a difference
to tone. Anyhow it suggests another sort of experiment. Thanks.

[crookedtune]

Anyone else, and I'd think you were trolling.

[monkeymonk]

Now, if a thief, of sorts, broke into your home and replaced your flute with a visually identical flute

He'd have to be able to copy my breath smell on the head joint and i wouldn't wish that on any theif

What would be interesting would be to line the bores of wooden flutes with a thin layer of delrin, say,
and see if different flute wood containers still
lend a different tonal quality to the flutes. If not, it would tend to confirm your hypothesis. If so, it would suggest
the vibrational properties of the underlying wood is making a difference.

Isnt that the same thing as a Revoli cast bore flute?

[jim stone]

Yes to the cast bore flute, only I'm not sure whether there are different flute-wood casings.
Maybe there are....

Just checked the site. Maybe not the best woods for experimental purposes; also I'm not clear how much wood there
really is compared to cast bore.

http://www.reviol.co.nz/out_of_focus/ca ... lutes.html

[Julia Delaney]

Years ago I spent some time with Patrick Olwell in his shop. He picked up a small billet of cocus and tapped it with a mallet. It had a distinctive, bell-like ring to it. He then picked up a piece of blackwood and tapped it. It sounded duller. There was a distinct difference between the two sounds produced when each billet was tapped. "So much for material not making a difference," he said.
I don't know if this would be a definitive test, or even if it would be relevant when talking about flutes made from different woods. He also said that for most players the small difference wouldn't matter.
I have been buying and selling and collecting flutes for years now. Each flute is different. If you pay close attention you can tell that two "identical" Olwell blackwood flutes sound as different, one from the other, as if they were made of different woods. They are all excellent flutes, but even flutes made from the same wood (from the same tree) would have some differences. I do think there is a difference between a flute made from cocus and one made from blackwood. With flutes -- unlike with lovers -- the differences signify that there is no clear need for monogamy.

[Terry McGee]

Years ago I spent some time with Patrick Olwell in his shop. He picked up a small billet of cocus and tapped it with a mallet. It had a distinctive, bell-like ring to it. He then picked up a piece of blackwood and tapped it. It sounded duller. There was a distinct difference between the two sounds produced when each billet was tapped. "So much for material not making a difference," he said.

It suggests cocuswood would make a better marimba than blackwood. Useful if you intend to tap your flute with a mallet rather than blowing into it!

I've made a few marimbas and did some testing of locally available timbers to see which ones work best. Quite interesting, and not always what you expect.

Terry

[Geoffrey Ellis]

Years ago I spent some time with Patrick Olwell in his shop. He picked up a small billet of cocus and tapped it with a mallet. It had a distinctive, bell-like ring to it. He then picked up a piece of blackwood and tapped it. It sounded duller. There was a distinct difference between the two sounds produced when each billet was tapped. "So much for material not making a difference," he said.

It suggests cocuswood would make a better marimba than blackwood. Useful if you intend to tap your flute with a mallet rather than blowing into it!

I've made a few marimbas and did some testing of locally available timbers to see which ones work best. Quite interesting, and not always what you expect.

Terry

At one point I had read some scholarly article by a gentleman who studied physics and acoustics who made the argument (one that I've since heard repeated from other sources) that woodwinds have no relationship to instruments that derive their sound from resonating wood. They do not work like guitars or violins or (as Terry points out) marimbas. They derive their tone from shaping and containing a vibrating column of air and not from the wood itself, providing that the wood has a reasonable amount of density and doesn't leak through its pores.

I, too have noticed that the woods I use sound very different when I tap them and some are quite "musical". But when I shape them into a flute, that musicality does not translate when the flute is played. At least not dramatically enough that I can hear it.

Speaking only for myself, when I make a flute and cut the embouchure hole and such, I do my best to be very consistent from flute to flute, but because it is done by hand, eye and ear, I don't kid myself that there are not plenty of inconsistencies that creep in. It makes evaluating subtle differences in flute timbers very tricky

[david_h]

http://members.iinet.net.au/~mtattersal ... erials.htm

[Geoffrey Ellis]

http://members.iinet.net.au/~mtattersal ... erials.htm

That's very interesting. I had read about the concrete flute in a couple of different places (including Terry's website).

To add some support to the conclusion put forth by the author, I've done an experiment using two very diverse woods. I made a pair of "Anasazi" flutes(end blown, with a mouthpiece similar to a shakuhachi), one from cocobolo (dense, oily) and curly redwood (super soft and porous).

The cocobolo cuts beautifully, and the untreated bore is so glassy I can look through it at the sky and see clouds reflected on the surface.

The curly redwood cuts so poorly that the inner surface of the bore looks like the surface of the moon! The drill tears it badly, creating a highly irregular surface.

The cocobolo flute plays easily with a bright tone and smooth response. The curly redwood is very sluggish, hard to produce a tone and it sounds dull and dusty by comparison. It weighs only a fraction of the weight of cocobolo. I haven't put them on a scale, but I'd say 25% or less than the weight of cocobolo.

However, if I start to treat the bore of the redwood, adding multiple coats of marine epoxy until the irregular surface is glassy looking as well (even though the bumps and craters remain) it becomes brighter and more responsive to the point that it sounds and plays so much like the cocobolo that it would be difficult to tell them apart if you were not holding the flute.

That's an extreme example, but it shows how important the bore surface is relative to the density of the material itself.

In the world of the Native American flute, this obsession with wood is even more pronounced, taking on an almost "mystical" significance. Interestingly, there really is more significance with those instruments because many makers utilize very soft woods and some don't treat the bore at all. So when a player handles a hardwood flute and plays it next to an untreated softwood flute, there really is a substantial difference that results from the wood choice because the softwood does not cut as cleanly.

[Terry McGee]

Good stuff there, Geoffrey. That experiment is very like my pine Prattens - the softwood requiring the pores to be filled before it would play at all.

At the same time I made that flute, I reamed some pieces of pine and gave them to Paul Dickens at University of New South Wales Physics to play with. (We used pine as we expected it would show up issues much more obviously than better woods.) He cut one up and submitted it to MicroCT scanning. You could see in the image how the wood fibres didn't shear off nicely but bent over at the surface of the cut, probably because they weren't supported closely by the surrounding fibres. Once these bent fibres got wet, they stood up again, making the bore furry and lossy to the vibrating air column. This presumably happens to all timbers to some extent, but reducing dramatically as the timber becomes more wood and less air. I imagine this would be one issue that caused western flute makers to opt for denser, finer timbers, as soon as they were available and their technology allowed them to work them.

I agree with your surmise that the surface is probably more important than the density - after all, this is where the vibrating air and the container have their greatest contact. The density may be important in providing stiffness to the container, but it's also possible that your marine epoxy adds significantly to that, especially if it soaks in much before setting. You're probably familiar with the cheaper maple recorders that use an impregnated bulking agent to make the relatively light maple act more like the finer, denser pearwood and boxwood.

Back on Redwood, and the observation that it used to be readily available in Australia for wall cladding, but seems to have disappeared. I don't see Western Red Cedar around as much either. I hope this means that growing environmental awareness has resulted in slowing the abuse of these wonderful native forests. One house cladding would yield a lot of flutes!

[Geoffrey Ellis]

Ah, I hadn't heard that about maple recorders, but it makes perfect sense. I'm sure you are right about the epoxy adding to the density--or at least making it behave as if it is much denser. My personal practice flute is a Pratten I made from curly maple (very beautiful) and did a similar trick. I reamed the bore, poured in marine epoxy thinned with alcohol and sloshed it around a bit to soak in, drained it and let it cure. This had the effect of both penetrating the pores of the wood and raising the grain (courtesy of the alcohol). I re-reamed it and then poured in a thicker coat of epoxy. When that cured, I reamed it again, and by that time the inner surface was harder and smoother than ordinary maple by quite a margin. Worked beautifully! This has the added advantage of making a bore that is waterproof, so the need for oiling or re-reaming in the future no longer exists.

I've been dreaming of getting a vacuum kiln for drying my flute timbers but also for doing resin injection under a vacuum. It would be interesting to see what can be done to soft woods like curly redwood. It is an exceptionally beautiful wood, and if the resin injection worked like it is supposed to, you could end up with a piece of eye candy that is as dense as delrin. Might be fun

You are right: the really amazing redwood is not easy to find any more, except as salvage, and that is a great thing! I've been lucky in obtaining amazing pieces of it because I live in the heart of redwood country and have some local contacts. However, twenty years from now I bet it will be very expensive to buy top quality redwood and it will be saved for special projects like guitar sound boards or specialty furniture. It is good for certain types of flutes (providing you treat the bore) but probably not a wood a lot of makers get into using.

[Julia Delaney]

Normally I would yield the issue, since I don't care one way or the other. I play both blackwood flutes and cocus flutes and delight in both. Points to Terry, however, for a facile put-down in the academic mode. Patrick claimed that the unique ringing sound obtained by tapping a square does in fact translate to something that the accomplished player picks up on. It's probably no accident that Nicholson flutes became thinner-walled than were previous flutes, such as Potters. When done right (fabricated and played) a cocus flute kind of leaps about in the hand. Players notice that the flute comes alive. This is also true with some bamboo flutes, which are very light in weight. Patrick had told me that certain bamboos have that quality while certain species don't. So the (theoretical -- i.e., unproved) physics maxim that the material is irrelevant seems off the mark to him. Not everything can be measured "scientifically." At least not yet.
Hearing ("playing") the flute as you play it-- and listening, as audience, at a distance -- are of course two different things. We should separate these two for the purpose of this discussion. For "playing" we should include seemingly subjective things, which science either can't measure or says do not exist. A scientist with sophisticated measuring devices, as audience, would probably not notice some very subtle things. One would be talking about a feedback loop between the musician and the instrument. Some very subtle things might affect this process.
Patrick says he noticed one day while staring at the wall chart of the inner ear in the ENT's office (where he'd ended up after too much intake of shop toxins), that the organs of the inner and middle ear were only a couple of inches from the chin. So he wondered whether some of these ineffables could be traveling from the flute headjoint, held tightly against the lower jaw, to the organs of the ear: mysterious hardware indeed, which also contains our balance mechanism, or gyroscope. The distance is less than about 3 inches. The vibrations of the flute, in particular a flute made of cocus, would be travelling through bone and be detected by the organs of the inner ear. This effect could hardly be considered irrelevant though it might not be measurable. To make Terry happy, and with due credit to Olwell, we might call this The Marimba Effect

[Geoffrey Ellis]

Julia,

I've heard from a number of players who value that feedback loop you describe. Some of them record their music and while they have acknowledged that the microphone doesn't necessarily distinguish between woods very easily, they themselves have a radically different experience of the woods as a player. As one of them put it, the vibration and "aliveness" of the wood in their hand had a direct effect on their playing and the musical choices that they were making as they played. In short, the character of the wood as they were perceiving it served to inspire them and enhance their experience.

[Terry McGee]

JD - I have never argued the material is irrelevant. Quite the contrary, I built my Pine Prattens in order to illustrate that some woods just can't make a desirable flute. I'd agree with the studies that indicate metals don't matter (mercury, sodium, potassium, plutonium and uranium being some obvious exceptions). My view on cocuswood and blackwood is that they are very similar in physical qualities and that we should therefore not expect too much difference between them.

Patrick has identified one big difference - cocus rings when struck and blackwood doesn't. I imagine (but don't know) that blackwood's ringing qualities are possibly impaired by the resin that permeates the wood. The South American rosewoods make fine marimbas.

But there are many reasons to doubt that this is relevant to flute tone, and we've gone through some of them earlier. But try yourself, I think you'll find little difference between cocus and flutes of other materials. To test a piece of wood for ringing, you need to suspend it from just above the quarter-wave point. Find this by "dividing" the flute in the middle, then "dividing" either half again. Hold the item between thumb and finger just above this point, and flick it with a forefinger released by the thumb at around the centre point. A length of cocus will ring loudly enough for my tuner to be able to get a fix on it a metre away. A piece in front of me, 348 x 40 x 40, for example rings at Db6 + 30 cents, just flicked with my finger. And that's a solid bar, I can only imagine how nicely it would sound if cut and arched like a marimba bar and given a resonator. Then again, who could afford a 5 octave chromatic marimba in cocuswood? And the inevitable argument about whether the resonators sound better if made in sterling silver or 18 carat gold?

Unfortunately, I don't seem to have an equivalent bar in blackwood - I've converted them all to round. Perhaps someone else can try the same test and report back?

But try a cocuswood flute with the same test and you will be disappointed. Firstly, instead of a sweet ring, you get a dull thunk. And pull the head out a bit, and the thunk goes down in pitch. We're just exciting the air inside. Cover the embouchure and the pitch changes dramatically. Flick a flute in another material and you get a similar result.

The bone conduction mechanism between mouth and ear is well known and easily demonstrated. If you have a tuning fork, strike it and apply the base of the stem to your teeth. Zing! Or hold a pair of tweezers by the handle end between your teeth, or teeth and lip, compress it between finger and thumb and slide your fingers off it so it springs open. I suspect (but again don't know) that an electric shaver when applied to the jaw will sound louder or different then when held close, for the same reason. And so it is possible that, if the flute were vibrating significantly, bone conduction would help us hear it. Instead of holding my cocuswood stick between finger and thumb, I tried pressing the nodal point to my chin, head twisted sideways so that the bar could be suspended there. It didn't change my perception of the ringing tone. I'd say it's not looking good for the body vibration theory.

Terry

[m31]

So wood -- at least dense woods -- make little, if any, timbral difference unless they will be left unpolished or rendered as xylophone blocks (or guitar tops). That critical design dimensions, head joint lining (ooh silver, sexy!), room acoustics and most important of all, player skill all trump flute material will never sway the most ardent, heavily invested flute collector.

If blackwood flute 1 sounds different from blackwood flute 2, all of us will reason that it must be due to design or dimensional differences.

If blackwood flute 1 sounds different from cocus flute 3, perhaps half of us will reason that it is due to the different woods.

Hmm. G0d forbid should ever a cocus and a boxwood flute sound identical.