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 theCasey Burns wrote: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.
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.