Thanks for the photos, Gandalfe. I was envisioning bamboo, which is the only type of shakuhachi that I have played. My bamboo shakuhachi sounds very woody. I do know what other materials would sound like. I will have to look for some recordings on the web. (My recorders are also wooden; I am a fan of woody tones).
My Boehm flute is solid silver, which I also love, but for a different feeling and different types of music. I have also played brass singing bowls, multi-metal singing bowls and crystal singing bowls, and I was struck by the dramatic tone differences produced by different materials. The one exception is a standard, transverse, wooden headjoint that I tried on a silver Boehm flute, which produced tones similar to those of all-metal flutes (with less control though). I was underwhelmed at that difference. I think I had been expecting more of a wooden flute tone.
David
I can't help myself, I have to post here. I also play various flutes--have had wooden Boehms, now have a bunch of flutes in both silver and plated. I have quite a few shakuhachi that I have collected over the years living in Japan, as well as an Okuralo--a silver plated vertical Boehm flute with shakuhachi-type head (rare, made for a few years in Japan between 1930-1940). I studied shakuhachi making for a few years as well, and have made a few. Finally, I collected a bunch of temple bells in Japan and a large number of singing bowls in India and Bangladesh.
There is something that needs to be understood. The effects of materials in bells and in flutes are completely different. Bells are idiophones--they make their sound by being struck and the sound is produced by the vibration of the material itself. Flutes are aerophones--the sound is almost exclusively made by the vibration of the air column. The material serves only to define the air column.
The parameters that define the flute sound, pertaining to the material (if it is reasonably rigid)j, are basically only two: bore geometry and bore smoothness. I know that this is a controversial topic, but scientific evidence is quite strong that this is the case. I don't know, for instance, if your shakuhachi is jiaru or jinashi. "Jiaru" refers to the interior of the bore being lined with a kind of putty (ji). Jinashi means that the interior is unputtied, although it can and usually is still coated with lacquer. Jiaru flutes tend to have a much brighter and more powerful sound. Jinashi flutes are generally more "woodly" and less focused. This has nothing to do with the material itself, rather the fact that the jinashi flute has a less smooth interior, and because the irregularities inside the bore tend to inhibit the higher harmonics.
I had for a time a Rudall Carte wooden Boehm flute, and also a Haynes wooden flute. They played almost identically to any silver flute. Studies have shown that that wooden flutes are slightly less efficient (on the order of 2 dB) than similar metal instruments because of micropores in the wood itself--if the bore is polished and unsealed. If the bore shows marked grain patterns, then you start to lose more efficiency, which is differential, affecting more the high harmonics--this the "woodier" sound.
This is all terribly complicated by the effects of small differences in bore geometry, which can have major effects on how the instrument plays, responds and sounds, whatever the material. All kinds of factors, including player expectations and just the feel of the instrument in the hands, get mixed up in our impressions and experiences playing different instruments.