me to introduce myself. I'm an Argentine flutemaker. I make
traditional, folk instruments from the Andes as well as other
projective instruments as bamboo saxophones and clarinets.
by my own experience and by readings about woodwind acoustics,
I conclude that the influence of material of the body is no
direct, contrarily as lots of musicians and flutemakers guess.
I looked at your web site, and found the material there very
interesting. The workmanship is beautiful, and my guess is
that the sound of the instruments is similarly appealing.
I will try to answer your questions below.
Have been them repeated by other physicians or laboratories,
independently of yours?
Are there other articles available about this item?
A number of similar listening tests
have been made, though none that I know of have been as carefully
designed to be free of errors as the tests I describe in the
Journal of the Acoustical Society of America, 49, p.520-523,
August 1971. No evidence for material effects has been brought
out by these. The most careful theortical and laboratory work
has been reported by John Backus, Effect of Wall Material
on the Steady State Tone Quality of Woodwind Instruments,
JASA 36, (1964), 1881-1887.
Also, I'm sure that in most cases the material doesn't resonate
toghether with the air column. But, Is it true in flutes or
horns made of very, very thin materials?
Is the air molecules energy enough to move thin metal, or
goat skin, or cardboard walls?
question is inspired in the Chinese flute D'tzu, which have
a silk-paper attached to its body. This membrane actually
Material effects are unimportant only
as long as three conditions are met:
1. The tube must be rigid
2. The interior surface must be smooth.
3. It must be impervious - leak-free and not spongy.
cylindrical tube can be sufficiently rigid even with quite
thin materials. However, a square tube must have thicker walls
to resist deformation, as Miller found in an experiment with
a square organ pipe made of thin sheet copper. You are quite
correct about the vibration of the membrane on some Chinese
flutes. On a Boehm flute, the pads are sufficiently deformable
that one can feel the keys vibrate under the fingers, though
the contribution to the radiated sound is negligible.
I found that wood polished with very fine sandpaper and finished
with 0000 steel wool has acoustical losses only very slightly
greater than a polished silver tube.
Many woods leak sufficiently to affect the tone quality if
they are not oiled. Maple is quite unsuitable in its dry state
- soaking in linseed oil will make it as good as any other.
Bamboo is quite impermeable - I would guess that you do not
need to treat your instruments.
hope you will find these answers helpful. Best of luck in
Some answers below. Best regards, John
Original Message -----
From: John Coltman
To: Angel Sampedro del Río
Sent: Wednesday, June 27, 2001 6:43 PM
Subject: Re: Material influence on flutes
Many woods leak sufficiently to affect the tone quality if
they are not oiled.
But, I underestand that is more due to small air cells or
wall irregularities than to vibrational properties of the
happen if you use a roughly finished metal wall?
rough surface will increase losses whether it is wood or metal.
internal wall of bamboo is quite impermeable, I find (more
correctly, I think that I find) differences in sound when
I seal or laquer it. Am I adding any "reflective property",
or I'm just making it smoother?
believe that it is primarily making it smoother, though it
is also possible that you are sealing small leaks.
Siguiendo con preguntas, ahora acerca de la influencia del
material y, en la flauta traversa, el espacio entre el corcho
y la embocadura y la placa del resonador:
Slomka mentioned me his axiom, "the more expensive the
material, the better the sound"!)
it's like jewelry. Natural emeralds are poor gems, full of
flaws, but are more highly prized than perfect artificial
ones, because they are more expensive.
of that anecdote, we realize that the SHAPE of this resonator
(...in Sankyo Flutes) is quite particular, concave center
with a convex rim -if I remember well.
Do you have any information about the action of this type
dimensions of the cavity beyond the mouth hole to the cork
are small compared to the wavelength, so the shape of this
cavity is unimportant - only its volume counts. One must not
change the shape very close to the mouth hole, where the jet
might be affected, but otherwise it doesn't matter if the
cork face is concave, convex or flat. The cork-cavity and
the mouth hole form a resonant system. At frequencies below
its resonance ( which is well above the flute range) the impedance
of the combination acts like that of an extra length of tubing,
keeping the octaves in tune. Without the cavity the octaves
are stretched. The effect of the cork cavity is mostly in
the third octave.
that it is another false belief...
The question was more related to the movement of air molecules,
preciselly close to a zone of maximum air movement. If I underestand
well, only a small ammount of energy of the flutist breath
is converted into sound waves. Is well known the belief among
flutists that the cork front must be metalic (and concave
following Sankyo Flutes) in order to reflect energized molecules
to the mouthpiece system. Does it happen or not?
Or the ammount of energy converted into sound is only related
with the aerodinamics of the mouthole?
there is no "reflection" in the usual sense. The
air between the mouthhole and the cork face is being sqeezed
and then expands each cycle, acting like a little spring.
This affects the resonance frequency, and therefore the intonation,
but the sound is produced by the vibration of air particles
flowing in and out of the mouthhole ,and the first open finger
impedance is a resistance which varies with frequency (?-please
correct me if is wrong). So, if I underestand well, this air
cell between the cork and the mouthole has a different resistance
at different frequencies. Does it make the air slower at low
frequencies than at high frequencies?
should use the word "impedance" here rather than
"resistance". Resitance is one type of impedance,
but it involves loss of energy, converting some of the motion
into heat. The impedance of the cork cavity is like that of
a capacitor, where pressure is required to squeeze the air
in, but when the pressure subsides or reverses, the air flows
thought that this correction of harmonical modes has been
made by the tapered head joint.
is true, but the cork cavity also plays a part, especially
at the highest frequencies
physician gave us an speech, and when we asked about the influence
of materials in Boehm flute, he mentioned some experiments
about the influence of molecular structure in high frequencies.
Do you know something about this?
only studies I am aware of concerning molecular structure
as affecting the tone quality of instruments, are those dealing
with those cases where the material is part of the sounding
mechanism, as in reeds, violin bodies, piano strings, etc.
example is a parallel traced between some Yamaha and Selmer
saxophones, where they seem to be equal in dimensions and
metal recipie, but the difference seems to be in the construction
method. I have not enough vocabulary in English, but very
roughly, the Selmer is "hammered" while the Yamaha
is shaped with a press. Selmer is supposed to be better for
this reason. Do you have any idea about this?
the final shape is different, I would not expect to find any
change that depended on how the material is formed.
the North of Argentina and Bolivia are a myriad of panflutes,
and traditionaly blown in quite different ways as the European
ones. The bass ones - called toyo or hacha-siku- are about
1.6m long, 2,5cm diam longer tube. Correctly blown, the sound
is very characteristic. The musician also put the mouthole
of the tube several centimeters below the lips, and somehow
exitates various harmonics, giving a tremendous sound. These
panflutes are made from a very very thin bamboo (less than
Every siku-player is absolutely convinced that this sound
is due to this bamboo. Also, when you slightly touch the far
end of the tube (closed, maximum pression variation) can feel
the bamboo wall vibrating. If this vibration affect the sound
or is negligible is another question, but is difficult to
convince others that it hasn't influence on sound. What's
your opinion of this phenomenon?
can believe that if the tube wall is thin, and if the tube
is not quite round, that it might vibrate appreciably. I think
you can appreciate that a tube of elliptical cross-section
would tend to expand, under pressure, to more nearly approach
a circle, and that a periodically alternating pressure could
cause a mode of vibration where one axis of the ellipse expands
as the other shrinks. A circular tube, however, already has
a cross section of maximum area for a given circumference,
and is very resistant to expansion. So a thin tube, not quite
round, could vibrate much more than is usual in a commercially
made instrument. Backus treats this case in one of his articles,
if I remember. It is certainly conceivable that the the sound
could be affected.
It would be interesting to make an instrument like this out
of plastic plumbing pipe, which is quite round and thick-walled,
and see if one can get the same sound quality. I believe in
controlled experiments, like the one performed many years
ago by a curve-ball pitcher who hurled a ball past three posts
set on a line, missing the first and last posts on their left
sides, and the middle one on its right side. This sent the
physicists back to the lab to ponder the forces of air on
a spinning sphere!
Entramos en las diferencias acústicas entre quenas
y flautas dulces y flautas traveseras de concierto
Why the notched end flutes like quenas and shakuhachi -without
trans-mouthpiece cavity- plays octaves in tune?
answer is - they don't. Here are the frequencies I measured
on a quena as I blew the first, second, third, and fourth
modes. Also shown are the ratios, which should be 1, 2 ,3,
and 4 for perfect intonation.
1208.4 3. 138
The last note is sharp by 1.25 semitones, which would be intolerable
in an orchestral flute.
that 1,25 semitones is intolerable not only for an orchestral
flute but for all music, I make quenas for 15 years. The standard
quena is tuned in G4, 6 holes at front and one back. Either
the G and A6 -fourth mode- could be played in a good quality
instrument by blowing harder or by uncovering a bit the back
hole. Believe me that if I found one of my quenas playing
1,25 semitones apart (say, A#6+25 cents) , I burn it in my
In fact, in almost cylindical bamboo quenas, the tendency
of this 4th mode is to be flat instead of sharp. In some of
these cases, we use for the A6 an optional fingering (closer
to the D fingering, 3rd mode)
Maybee player's embouchure plays a rol here. Maybee is due
to the inverse conical shape (as the renaissance flute), although
I dont believe in that posibility.
Sometimes -really almost always- quenas are done with a partially
covered far end, which makes the instrument as it were longer
than it actually is. It is an ancient tradition that I don't
use. I noticed that in that cases detunings as you mention
are quite common for the G
are correct about the restricted end hole. It adds to the
stetch just like the restricted mouth hole does. The quena
I measured has such an end. I don't have a quena without this
feature, but I measured a Mexican tarahumara which is cylindrical
and has a whistle type mouth piece. Results are:
Mode Sharpness relative to 1, cents (hundredths of a semitone}
Here the sharpening is still very evident, though not as great
as for the quena. A row of finger holes rather than a single
large opening gives an octave shrink, so that for many notes
the lack of a cork cavity may compensate. The conical bore
may help too. Have you actually measured the intonation of
your quenas with a tuner? The ear likes a stretched octave,
particularly in the high frequencies. A true octave sounds
underestand from this table that mode 2 is 39 cents sharper
than the correct value (so, 1239 cents instead of 1200). It
is a lot!!!
Yes I always tune my quenas with a Chromatic tuner, Korg DTM-12.
I also noticed that sometimes flutemakers commit self-hoax
when tune their own instruments, by blowing harder or softer,
either using a tuner or not.