Flute Tone Investigations
"n"
- A Picklist of Potential Investigations
I thought it might be useful
to compile a list of issues we may wish to look into, in our quest to
understand better the factors that influence the tone we perceive from
the flute.
It might take some time to
get to all of these, and some of them might fall by the wayside,
rendered irrelevant by other findings. And the order they are listed in
may not be the order we investigate them in.
The titles are indicative
only, and may be replaced by something more appropriate suggested by the
content of the investigation.
And there might be a burning
issue that has been bothering you. Let me know, and if it seems
potentially profitable (intellectually, not necessarily financially!)
and it seems likely we can investigate it, we'll chuck it
on the list!
Potential Investigations
1. Of harmonics and levels
In our second article, we saw
that, at least in Paul Davis' playing of the Three Maries, the second
harmonic was the overwhelming contributor, with the fundamental and
higher order harmonics often well below in level. But how far down
does a harmonic have to be before it becomes insignificant? And
does the same level down apply to all harmonics, or are more distant
harmonics at the same level more noticeable?
Can we employ simple
filtering devices to identify and quantify the perceived contribution of
the different harmonics? Or use harmonic synthesis to explore our
perceptions? Can we relate words like "reedy" to reed
instruments?
2. Development of tools
We'll need to develop our own
tools to do these analyses. In the early days, these will probably
take the form of manual data capture and spreadsheet analysers, but,
just as RTTA has revolutionised pitch measurement, it would be really
good to develop automated real-time tools for tonal analysis.
Position Vacant: Senior
Programmer. Apply within. Remuneration package to be
negotiated, but limited in form to personal satisfaction.
3. Jet offset exploration
What is jet offset, how do we
invoke it, what does it do, how do we perceive it? Can we
associate what it looks like with what it sounds like?
4. Types of flutes
If we have ambitions to be
able to detect and measure differences in flute tones, then comparing
Boehm, Conical and plain Cylindrical flutes should be easy. Yeah?
And once we've done that, the next step is investigating the difference
between big-bore Pratten's, medium bore Rudalls and small bore GLPs.
And if we can do that ....
5. Types of Players
While Gregor in the paper
referred to in the Introduction to this series clearly showed the
different metals produced no differences, he also proved that different
players make all the difference. His players were probably pretty
much "out of the conservatoire mould" by comparison to the range of
playing backgrounds our community comprises. Can we characterise
players in this community in any meaningful way, or is it a complete
spectrum or jumble? Are some sorts of players predisposed to
certain kinds of flutes? Are there some tones that we all admire, and
others on which we are divided? Can you move along the
spectrum if you want to? Can our tools help you move?
6. Technical resources
What equipment and software
are being used in these investigations? What are their
limitations, and are these impacting on the quality of the measurements?
Do they impact on the findings? How good enough is near enough?
7. Crunch the numbers
Once we settle on some
measurement philosophies that seem to have the capacity to bear fruit,
we have to settle on some number crunching protocols. These need
to be able to stand up to examination, and others might like to see if
they can replicate the results. Knock yourself out!
8. Further Reading
A lot has been said and done
in this field over the years, admittedly almost all in terms of other
kinds of flutes. When is it applicable and when is it not
applicable to our kind of flutes? A lot of what is available is on the web.
Links and maybe comments.
9. Effects of embouchure cuts
and chimney depth
Different embouchure cuts and
chimney depth produce audibly different flute tones. If we can
hear it, hopefully we'll be able to see it, and understand why.
10. At the Foot of the Matter
Early flutes had Short D
feet, 19th century flutes had C feet, and modern Irish flute have a
choice of Short D, Long D and C feet. Can we detect a difference
in sound level or quality? Are there gains and losses?
11. Stopper position and tone
Elsewhere on this site, we've
examined the effect of stopper position on tuning. But what it its
effect on tone? Can our tools tell us?
12. Effects of materials
We saw in the introduction
that the significance of various metals in metal flute construction has
been disproved, by both listening trials and in careful measurement.
But our materials are not so limited in range - is it possible that they
still do have an effect? Can we tell the difference between a
blackwood and a pine Prattens made with the same measurements and tools?
Can we go on from there to determine which of the possible
characteristics are responsible for what tonal differences? Does this
then suggest what materials will be better than others, or does it come
down to a balance in taste? Can we detect metal head liners, full
and partial, and metal lip plates? Does oiling polymer make any
sense? Do ebony and blackwood differ in tone?
13. What's best? Easy, or
Manageable Pain?
It's often put forward that
an easy-blowing flute may not be capable of as good a tone as some more
difficult-to-play instruments. Can we find anything to support
this view? Can a flute be too difficult to play? Or too
easy?
14. Only flat for Wusses
First half 19th century
flutes tended to have low notes that tended flat. Players learned
to accommodate this. How did they do this, and how did it work? Modern flutes don't have to replicate the
flat-footed
feature, but some do. Some players can't handle it, others can't
seem to live without it. Is this just laziness on the part of the
maker, coupled with hairy-chest syndrome on the part of the player, or
can we detect real advantages in this approach? If so, can we give
guidance to those who would like to play that way, but so far can't?
15. The Dark Side, Luke
What contributes to
"darkness" in Irish flute playing? Can we measure darkness?
Can we learn darkness? Can we control the dark side? What
proportion of darkness lies in the flute and what proportion in the
player? Is Cut-off Frequency implicated?
16. Spectrum or Cepstrum?
A Cepstrum is a single
spectrum which attempts to replace a family of spectra. (Cepstrum,
pronounced with a hard C, is a manufactured word - spectrum with the
first four letters reversed.) We've seen that the spectra of
different notes varies significantly, but is it possible that we could
still use a Cepstrum to describe a flute? It would be handy, but
would it be too misleading? Can several cepstra adequately define a
flute (eg low notes, LH, 2nd octave)?
17. Signal to Noise Ratio, or
Clarity
You've probably encountered
flutes that are magnificently clear, and others that are wallowing in
noise. Can we develop a tool to measure signal-to-noise ratio like
the HiFi people do? But is it that simple? Is there good
noise and bad noise, and if so, what's the difference? Can our
tool learn the difference? Can we identify the noise sources?
18. Dynamic vs steady state
It's often been noted that
our ability to recognise the tone of an instrument (eg differentiate
between a clarinet and a violin) is much reduced if the starting
transient is taken off or disguised. How does the starting
transient of our flute affect our perception of its tone quality?
What defines and characterises a starting transient in a music that
largely employs finger articulation?
19. Undercutting
Can we detect the effects of
undercutting on tone? Just how sharp would our measuring tools
have to be?
20. Low whistle?
Can we identify the
differences in tone between the D flute and low D whistle? (Heh
heh, if not, you'd have to ask are we getting anywhere!)
21. Projection - urban myth or
exploitable reality?
It's often argued that some
flutes sound no louder up close but "project better". Can we find
any evidence to support the claim?
How different in spectral
content, amplitude and phase are the tones leaving the embouchure and
other end of the flute? How far back do we have to be to hear them
combined? I.E., where does the near-field end and the free-field
begin? Do some flutes or playing styles take better advantage of
the ear's most sensitive frequency bands? Does the flute carry
better than some other instruments simply because it is louder? Does the
player seeking projection above a mix of other instruments have to
tailor their tone to avoid being masked by the particular mix of
instruments - ie do they need to find some unclaimed spectral space?
Do they do this naturally or consciously?
22. Flute add-ons - snakeoil or
what?
Fluteplayers, even the best
of us, are never happy with our tone. This makes us easy marks in
terms of scam add-on products and treatments. Which is not to say
that all add-on products or treatments are scams. So, clearly we
need to be able to tell between them. If we can develop tone
measurement tools good enough to investigate the issues above, they
should also be able to confirm changes brought by the add-ons.
23. New heads on old flutes
It's my routine experience
that a 19th century flute usually benefits dramatically from being
fitted with a new head. I'd feel better about that, if I could
always confidently point to what's wrong with the old head.
Sometimes it's obvious, and that's fine. But I've had many cases
of old heads that just don't sound good. I've tested them for
leakage, replaced stoppers, inspected them for damage to the edge or
chimney and found nothing. Clearly I need to look harder!
24. Instabilities
We've probably all come
across examples of instabilities in flutes. Cover the embouchure
too much or blow too hard, and some notes start to go wobbly - that kind of thing.
What's actually happening here? Are there more than one type of
instability?
25. Musicality
What contributes to a feeling
of musicality in a flute? What detracts from it? Do we take into account tone, tuning,
responsiveness, clarity, articulation? Others? Do mechanical matters
(easy and operation of keys, firmness of tenons) impact on such feelings
(ie are distractions problematic for our perception of the whole?)
26. Responsiveness
What is responsiveness? What
contributes to it in a flute? Is it just efficiency (the amount of sound
produced divided by the amount of air flow)? Or do matters like
articulation contribute to our perception? How sensitive are we to
differences in adjacent notes. What aspects of adjacent notes impact on
this - tuning, volume, tone,
27. The Effects of Aging
Does a new flute really
improve with age, or is it just that we get better at blowing it. Or
both? If a maker were to take a well blown-in flute and return the bore
to original state, would the blowing-in process be reversed, the clock
reset? Can we detect "falling asleep" - the oft-reported feeling that
old flutes need reawakening. What changes during re-awakeing? Moisture
content? Efficiency? Tone? Tuning?
28. Boundary layer vs blowing in
It's argued by acousticians
that a boundary layer exists at the walls of a woodwind, separating the
free flowing air in the middle from the air that is in contact with the
walls. Consequently, a little roughness of the walls shouldn't
matter. The boundary layer is usually deemed to be about 0.1mm
thick. If so, it seems that this concept is in some disagreement
with the notion that a flute can be "blown in" - surely the boundary
layer will insulate the air from any changes to the wall material or
surface. Can these concepts co-exist peaceably?
29. Blowing in - blowing out?
There is a view that
clarinets and oboes have a finite lifetime - that they will "blow out". It's
hard to see any major difference between the clarinet and the flute, yet
vintage flute players don't seem to make the same observation.
What's the story? Is it possible that what the reed players call
"blowing out" is the physical deformation of the bore we call
strangulation? If so, we are familiar with it.
30. Harmonic Dynamics
Is it enough, for the
purposes of investigating flute tone, to take a note at a time, or do we
need to dissect that note further to see the full picture? For example,
does the final blend of harmonics build up together at the start of the
note, or do some develop later than others? Can we hear the difference?
Do players vary their harmonic mix during a note, and is it conscious or
unconscious? Is it something that they only have time for in slow
pieces? Is it a significant factor in the player's unique sound
signature? What tools are useful in determining and visualising this?
31. Dynamic vs steady state
It's often been noted that
our ability to recognise the tone of an instrument (eg differentiate
between a clarinet and a violin) is much reduced if the starting
transient is taken off or disguised. How does the starting transient of
our flute affect our perception of its tone quality? What defines and
characterises a starting transient in a music that largely employs
finger articulation?
32. Perception thresholds
A player is a lot closer to
the flute than the average audience member, but not much closer than
another player in the next seat. Can we detect a difference in
perception thresholds between all three? Are any differences adequately
explained by drop in volume level with increasing distance? Does
amplification (or recording and replay) to realistic levels restore the
ability to perceive fine detail? Or is the increasing proportion of
reflected to direct sound responsible for blurring fine detail? Is a
small amount of blurring a good or a bad thing? (Analogous to soft focus
in portrait photography?)
33. Vibration
Flute players often comment
on the excitement of feeling the flute vibrating under their fingertips.
But is it the flute vibrating, or the air column? If it's the flute,
isn't that a bad thing - the pliable walls of the container sucking
energy out of the vibrating air column inside, and dissipating it as
useless heat? If it's the air column, why do some flutes seem to do it
more than others? Efficiency of the flute? Size of the fingerholes?
Other? What other information passes back from the flute to its player?
34. Resistance
Players talk about the
resistance offered by the flute. It can be too high (the flute is
stuffy), or too low (feels like blowing into a vacuum). Can we actually
detect "back pressure" at the embouchure? Is that what we call
"resistance"? Or are we assessing audible responses, eg the ratio
between the effort we put in and the amount of sound that comes out, or
tone-related changes?
35. Edgy, but not nice
Sharp edges in the wrong
places can generate a nasty edgy noise. I suspect it's something
like scrape modulation noise in an analog tape recorder. Can we
detect it by measurement? Can we set an acceptable maximum level
for this sort of noise? Can we devise a test that helps us find
the location of the problem? What remedies are the most effective?
Would a "wind-tunnel" approach (in our case, passing large volumes of
air through the flute) enable us to exaggerate any effects and make
problems easier to detect and deal with?
36. The effects of key holes
Some have argued that the
performance of a keyless version of a 19th century flute will suffer
unless the volume of the holes under the pads has been factored into the
bore. My perception is that there is actually a gain because any
acoustic losses are more than overcome by fewer aerodynamic issues.
Are either of us right, or both of us wrong?
37. Just how precise?
Does a flute maker need to
work to 0.01mm precision, as has been claimed? What is the first
indicator of insufficiently accurate work - tuning, tone, response, a
combination, other? Which parts of the flute are most demanding of
precision? Which are least? In the light of findings, how do
we interpret Ward's and Rockstro's very opposed comments on chambering?
What could chambering mean, and can we find evidence of it?
38. Vowels
Can the flute player emulate
vowels in singing? Is that something we do when approaching airs?
Is it conscious or subconscious? How would vowels present in terms
of harmonic structure? Does "hearing the words in our head" change
the sounds we make? Does it assist listeners to appreciate the
air?
39. Just blow in the end, OK?
It's bothered me for a long
time that whistle players such as Mary Bergin and the late Mico Russell
could produce tones from the common Generation whistle that were
radically more attractive than the tones I could produce. What's
going on there? On the face of it, the scope for manipulating tone
on a whistle is not great.
40. It's all in the way you
hold your mouth...
Like the one above, it's
sometimes claimed that you can alter the tone of the flute by the way
you hold your mouth, throat, vocal chords etc. A very interesting
one because it's hard to see much scope for interaction across the jet
(the pushing string uphill problem). But it should be possible to test
for it by adding a variable volume artificial mouth at the back of the
artificial lips in an artificial flute blower. And perhaps a microphone
in the mouth?
41. Genetically
predisposed to flute
I often use that expression
to cover those people who seem to be able to get luscious tone on day 1,
can play the most difficult tunes effortlessly, and can play flutes that
the rest of us would send for repair without seeming to notice a
problem. Can one be genetically predisposed to flute, or have they
just put in the hard yards and are now reaping the benefit? Can we
discern any physical (or mental) features that could be part of their
predisposition?
n. Other things we'd
like to know
I keep thinking of other
things we would like to know about the flute and flute playing, that
nobody seems to have worked out, or at least written down somewhere
where we can find it. So, I thought I'd record them here so they
don't get away, until I can figure out a better place to keep such a
list! Feel free to add to it!
-
Which fabric swabs water
the best?
-
Which oil slows the
intake of water the most?
-
How quickly does a flute
take on water when played
-
How much air do we pump
through a flute per hour
-
What impact on our
cardio-vascular system does energetic flute playing have?
-
What is the distribution
of temperature along a flute?
-
What is the rate of rise
of temperature in a flute as we start to play?
-
When does the temperature
reach equilibrium?
-
Does the intonation
(tuning) of an old flute change as it is blown back in?
-
Can a bad or weak player
cause a flute to misbehave, and a good player cause it to come back
into line? (The subject of an old claim.) If these
changes are detectable, are they in the form of pitch or performance
changes?
Conclusions
Whoa, that should be enough to go on with for the
moment! And we've strayed somewhat from the central issue of flute tone,
but that's OK, they're still good questions we'd like definitive answers
to. I'll get to them as time permits, and as I build up and
test my resources. Keep in touch!
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