On the tonal characteristics of different woods

[Migraine Stick]

All,

It strikes me that Casey's folk flutes provide an excellent natural experiment to get at the differences between blackwood and box. The flutes are all very similar in construction, so within small variations, any overall differences in tone (ideally averaged over many players) could be ascribed to the wood. The hard part would be getting the data -- a few folks would have to play through a bunch of the flutes right before shipping a big batch or maybe at a store that has a big stock -- but once the recordings were made, spectra could be calculated and averaged to see if there were any characteristic differences (a la the Widholm et al. paper Terry mentions on his website). If the blackwood flutes looked more like Terry's spectral analysis of "reediness," that would be some real evidence that blackwood sounds more reedy and box more rounded. Completely impractical idea, but fun to think about (for me, probably a ton of people in the shop is the stuff of nightmares for Casey).

Cheers,
Matt

[Geoffrey Ellis]

I've given a lot of thought over the years as to how an effective comparison of woods can actually be achieved, and the recent thread on cocus wood has gotten me thinking of it again (as well as this topic).

In a nutshell, I think the difficulty will always lie with the fact that players are too different and that tapered bore flutes that have an embouchure hole cut by a human being will always have so many tiny variables built into them that any comparison would be hopelessly subjective (assuming that one is trying to create a truly objective test).

To make a really "scientific" comparison of tone woods, there would have to be some way to overcome these variables. It might work better to use cylindrical bore whistles. If one could use modern machining equipment to create a mouthpiece attachment that would fit onto a wooden body, then it might be possible to greatly reduce the variables. If the mouthpieces were all made from the same material with very tightly controlled tolerances, then they could be attached to various wooden bodies that have also been precision machined. One could use a variety of woods, and they can be left untreated by any finish (or all treated exactly the same). As long as wall thickness is the same, along with hole placement and size it might be possible to create a situation where the only significant variable is the wood. One could even use some type of pump to introduce a controlled airstream that is exactly the same all the time.

Once that is done, one can listen to all the woods, record them, spectrum analyze them, etc..

Now, I don't know who would go to the trouble to do such an experiment, but I bet a lot of makers and players would be interested to hear the results.

[Terry McGee]

It is tricky. In one of the classic experiments, they made plastic moulded embouchure sections into which they plugged various tubes. That was intended to get around the variability of embouchure problem. Then they mounted the tubes on a holder, so that the blindfolded player couldn't touch the tubes, thus getting around the tactile identification problem. Problem is of course the player was then limited to one note. So getting around the criticisms people had made of other experiments brought on its own list of criticisms. How, people fulminated, can you judge a flute material through a plastic embouchure on the basis of one note?

I can imagine that some climate scientists would prefer to stay in bed in the morning rather than face the barrage of criticism they have to endure daily. I'm looking at you, Mr Murdock....

Terry

[Geoffrey Ellis]

I could see how players might balk at such an experiment, given its limitations. However, a single note played with a controlled velocity of air at the very least would allow measurement of some kind. If someone could compare half a dozen different woods and see how much variation there is in harmonics and such, perhaps it might have some value.

As a maker, I find this topic to be of great interest because it bears directly on choices I make related to my work. As I've said before, I think wood choice is important and that there certainly are subtle differences between different materials. However, I don't think anything is served by building a mythology around certain flute timbers, making them more than they are.

On the topic of how the sound is perceived by the player vs. the audience: I was at a flute festival with Ron Korb (not an ITM player, but a seriously skilled Boehm flute player). He was talking about the difference between silver and gold flutes. So we tested a bunch of flutes and head joints that he had, him playing them and me listening from about six feet away. I could not detect the slightest difference between them. Nothing. And I'm used to listening for subtle differences when I'm voicing and tuning instruments. He, on the other hand, was having different experiences as the player, and could tell a difference between the silver and the gold.

He did admit, however, that the differences were so slight as to be almost undetectable. He commented on how the materials debate/myths are very much alive in the Boehm flute world as well.

Personally, I'm very glad that there is a subjective experience with woods that can't be quantified. I'm not keen to be replaced by a 3D printer

[Casey Burns]

Setting aside the potential shop nightmares for an instant (the nightmare would be getting my workshop presentable!), one factor to consider is that when I am doing a batch of flutes, and from batch to batch, I am trying to get them all to play more or less in a way that I prefer, and to all play the same, regardless of the wood type. To a point, as the endpoint of how I want my flutes to play each time is constantly evolving.

What seems to make more of a difference than wood type is microscopic differences in the cut of an embouchure, tone hole undercutting, and other factors. My flutes are not so templated out that they have stopped evolving. From batch to batch and from flute to flute I am constantly trying to make each one play better than the previous one. Thus flutes from different batches will have different qualities, based on this evolution. And then some days I will cut the embouchures one way and another day I will cut them slightly different - varying the slope of the sides for example (one of many aspects). Also I leave a few variations to chance within narrow margins and observe the results, such as the wall thickness at the embouchure. These all have a bigger bearing on tone than wood type. It also keeps making the same flute over and over interesting because it isn't the same flute over and over.

Add to this the playing-in, the slight dimension changes that occur over time (these usually improve tone as the bore goes from round to ever so slightly oval, according to my observations), wear and tear.

Its more akin to the differing properties of wine varietals year to year and sometimes bottle to bottle, than a mere simple difference between woods.

One thing for certain about the Folk Flutes: these are my most popular product and the making of many of them (last year it was way over 100) gives me lots of practice in tuning and voicing flutes, making them all work well for most players. This carries over to my more expensive instruments. Like anything musical, practice is important.

[Migraine Stick]

I think that the small variations in construction are actually a plus within the same style of flute -- that's the way actual flutes are made that people feel they hear a difference between, so it seems like a good target for a test. My guess would be that those small variations would either be random, and so would average out, or would be characteristic to the wood (e.g., achievable sharpness of tone hole) and so are an intrinsic part of the difference. It seems to me that the problem is sample size -- there's likely a large difference in spectra between players, so you'd want a lot of recordings to average that out. Looking at average spectra seems like a nice objective approach to me, and in line with previous work.

To keep it quick, everyone could just blow a low d on every flute (you'd still need a bunch of people and a bunch of the same type of flutes, like the folk flutes--maybe this could be a festival thing). Or we could have a kickstarter campaign to pay Casey to record a low d for every folk flute he makes, and for a UNSW grad student to help write it up. I'd also like a pony, if we do that.

(I am a climate scientist, but fortunately not important enough to be singled out for criticism.)

Cheers,
Matt

[Casey Burns]

No kickstarter campaigns please! I'd rather spend my time making flutes. Also, there would be an additional factor - my daily variation. Some days I am a better flute player than others. Some days my shop is warmer than others. Thus the low D recordings wouldn't give us any useful data. Or it would give more data about me than the flutes I am playing. The Quantum Mechanics Observer Effect applies itself to flutemaking definitely.

[Casey Burns]

On the other hand, my wife Nancy just asked how much money would be raised for me to do this. $10,000 - $15,000 or more? Then we're talking......

[Geoffrey Ellis]

What seems to make more of a difference than wood type is microscopic differences in the cut of an embouchure, tone hole undercutting, and other factors. My flutes are not so templated out that they have stopped evolving. From batch to batch and from flute to flute I am constantly trying to make each one play better than the previous one. Thus flutes from different batches will have different qualities, based on this evolution. And then some days I will cut the embouchures one way and another day I will cut them slightly different - varying the slope of the sides for example (one of many aspects). Also I leave a few variations to chance within narrow margins and observe the results, such as the wall thickness at the embouchure. These all have a bigger bearing on tone than wood type. It also keeps making the same flute over and over interesting because it isn't the same flute over and over.

Yes, this is as it should be. The human factor is the most important part of the equation and as much as I value consistency I have no desire to make them so uniform that I feel like I'm pressing buttons in a widget factory.

[Casey Burns]

I feel like I'm pressing buttons in a widget factory.

Wait a minute! You mean its not supposed to be like that?

[Geoffrey Ellis]

I feel like I'm pressing buttons in a widget factory.

Wait a minute! You mean its not supposed to be like that?

[cory little]

My experience as a vibrational woodworker (drums, flutes, didges, basses, ext..) has led me to believe that the surface texture of the wood, the stiffness, as well as the wood density, have notable effect on the tone of the instrument, but not nearly as much as the thickness.. There is a world of difference between a wood flute with a quarter inch thick wall as one thinned down to 1/8".. This, in effect, has proven to me there is relevant vibrations traveling through wood, so wood selection has high importance..

The aspects of the different woods are most prevalent in a very thin flute.. Heavier, denser woods will maintain a firm containment of the vibration, projecting a "cleaner" sound.. sometimes refered to as "hard". The softer woods absorb more vibration as it travels down the barrel.. a softwood flute that is too thin will loose notable volume due to sound absorption. This absorbed vibrational energy results in a "softer" sound, because the same sounds that sound penetrating to your ear are the first ones to get trapped by the wood.

[monkeymonk]

I think that the small variations in construction are actually a plus within the same style of flute -- that's the way actual flutes are made that people feel they hear a difference between, so it seems like a good target for a test. My guess would be that those small variations would either be random, and so would average out, or would be characteristic to the wood (e.g., achievable sharpness of tone hole) and so are an intrinsic part of the difference. It seems to me that the problem is sample size -- there's likely a large difference in spectra between players, so you'd want a lot of recordings to average that out. Looking at average spectra seems like a nice objective approach to me, and in line with previous work.

This was essentially my point in the cocus wood thread which was to... "cut down that variability in construction by widening your survey base and creating many different flutes made the same way but out of 2 different materials." However, Matt is presenting it much, much better than i did. It's basically the law of large numbers. I would add that weights should be added to each end of the flute so that they all weight the same. That way, aside from smell and texture it would be difficult to sense the wood type if blindfolded.