I am wondering, regarding this topic, if anyone has checked something
else regarding resonances that just seem so obvious to me.
First of all, you cannot change a round pipe into a square one or
vice-versa, nor a wooden pipe into a metal one. You can build a
diapason in either type, same scale and voiced similarly, perform a
spectrum analysis. But that isn't the criteria I speak of here.
My criteria is different, and, I think, more noticeable than small
harmonic differences between similar scales. First of all, the speed
at which a pipe speaks plus its first intonation -- between the two
different materials -- is what is so different, to my ear. Not that
harmonic content can be discounted, of course. But the promptness and
initial "honk" of a pipe is very distinctive, to me. Every pipe
changes tone during the initial thrust of air. The manner in which it
straightens out in the pipe is, to my ear, the single most distinctive
difference of that rank.
The second thing is the "breathiness" (or in some cases, stringiness)
of a wood pipe, versus a metal one. There is absolutely no way a
builder of pipes can create the sound of the sharp languid and upper
leaf of a metal pipe in wood, nor would he want to. I would think that
when air strikes a thick, soft leaf material, it's going to be split
with more distance from the two streams than were it a metal leaf.
So its oscillation would have a bit wider "bandwidth." In pipes that
don't oscillate like that, the impedance of the thicker leaf in wood
would be greater, increasing the back-pressure slightly, hence simulat-
ing a slightly lower upper leaf perhaps. The angle of the bevel also
creates a change in diameter at the same point, whereas in a metal
pipe, it usually doesn't.
The third thing I have noticed is the interplay between wood pipes,
I think because of the flat wooden sides which are close to each other.
Metal pipes don't seem to intervibrate when they play, but wooden pipes
definitely do. You can even feel their next-door neighbors vibrating
in response, but you can't feel a metal round pipe next to the playing
pipe doing that.
And the fourth thing is the way I listen to a wooden pipe cut off. It
does it with a "whu" or a "whoof" very quick sort-of tone. It's never
perfectly clean and crisp. I am sure that all these things can be seen
on an analyzer, but are probably discounted or tuned out.
So I think what I am noticing about wooden pipes are their peripheral
sounds which do not equate directly to harmonic content, but which
describe the pipe better than anything else. It's the same way we
recognize voices over the telephone. Two voices may sound the same,
but the S's and the Z's, the P's and T's and K 's are different, to me.
So all it usually takes is a sentence, and I've got them.
I wonder if pipes could not be understood and categorized that way,
too? Someone who understands the characteristics of speech might be
interested in taking a stab at it from a completely different