Experiments of players effects on the altissimo register tones in the clarinet

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Experiments of players effects on the altissimo
register tones in the clarinet

• Mitsuru Ikushima and Shigeru Yoshikawa (Graduate
  School of Kyushu University)

2
A long-term debate

• Backus (1985)
• Usually the effects of players vocal tract
  are ignored because player Z1 ltlt instruments
  Z2.
• Fritz and Wolfe (2005)
• Clarinet tones are affected by the players
  vocal tract
• because Z1 is large when played in the
  altissimo register or played using pitch bending
  and slur.
• Chen, Smith, and Wolfe (2008)
• A precise adjustment of vocal-tract resonance
  with
• high acoustic impedance is needed to play
  altissimo.

3
Vocal tract shape and Input impedance
(after C. Fritz and
J, Wolfe (2005))
???
High register
1 kHz ? fundamental freq. of D6 (D6 altissimo
register)
???
Low register
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Simplified theory

• Self-excitation condition
• (after Fletcher and Rossings textbook)

reed width reed opening air
density reed damping const. reed
resonance freq. reed moving surface
reed mass
phase condition amplitude condition
Z1 might cause some changes in reed vibration if
Z1 is comparable with Z2.
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Modelling

• impedances of simplified models

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Plots of Z1, Z2, and Z1 Z2
Z1 Z2 ? Z2
Z1 Z2 ? Z2
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Z1 Z2 when the Q of the vocal tract is
changed.
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Research Objective

• The effects of the players vocal tract should be
  confirmed using an artificially blowing system of
  the clarinet.
• Fritz and Wolfe (2005) used actual players to
  measure the vocal tract effects (players might
  change their embouchure as well as their vocal
  tract).

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Research flow

• Manufacture of a blowing system
• mouth section (oral cavity)
• vocal tract section (several models)
• impulse response measurement
• Measurement of clarinet tones
• recording of the blown tones
• FFT analysis

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Mechanical models of vocal tract

• oral cavity pharynx larynx
• simple geometry and material
• (vinyl chloride plastic tubes)

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Oral cavity model

• artificial lips made of silicon rubber ?
• (a pressing force is applied by two
  thumbscrews)
• the cavity volume (a little larger)
• a constant blowing pressure monitored by
• a digital manometer ?

?
?
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Larynx model

• Six kinds of plastic tubes with different
  interiors
• Models 13
• inner radius 31.4 mm, larynx length 69.6 mm,
• total length 132 mm, almost constant cross
  section,
• similar resonant frequencies and different Q
  values.
• Models 46
• inner radius 16.3 mm, larynx length 83 mm,
• total length 150 mm, oral cavity side narrowed,
• resonant freqs. different from those of models
  13.

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Photos of larynx models

• Models 13
• Models 46

1
2
3
4
5
6
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Impulse response of our blowing device

• Resonance characteristics of our models (oral
  cavity
• larynx) are measured.

quasi-exponential horn loudspeaker
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Frequency characteristics of models 1 - 3
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Frequency characteristics of models 4 - 6
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Summary of blowing devices
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Clarinet tone measurement

• measurement sequence
• notes measured

• installing the model
• setting up the blowing pressure (45 kPa)
• recording, and removing the model to measure the
  reed opening

normal register C4, G5, C6 altissimo
register D6, F6,G6
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Experiment Scene
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Blowing Device and Clarinet
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Measurement result Normal register
Reference level at the fundamental freq. of
model 1
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Measurement result Altissimo register D6
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Altissimo tone D6 vs. Blowing device resonance
The blowing device resonance cannot afford
appreciable effects to an altissimo tone D6.
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Discussion Conflict with Wolfe (2005)

• ? Problems in our system and measurement
• (1) Matching of the frequency characteristics
  between
• the instrument and the blowing devices
• (2) the size of the oral cavity part
• (3) setting of the blowing pressure (4 to 5 kPa
  was too
• high to examine minor differences in
  tones)

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Discussion Conflict with Wolfe (2005)

• ? Problems in the preceding study
• Players lips and jaw will be inevitably
  moved when he
• changes his vocal tract shape?
• ?
• Then, the reed opening and damping might be
  changed?
• ?
• As the result, the timbre (tonal spectrum
  structure)
• might be changed?

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Effects of reed opening
Models 4 5 weaker 4th
5th harmonics
?
D6
?
?
Reed opening might affect the sound spectra??
?
?
?
?
?
Model 2 smaller reed opening
smaller sound pressure Models 4 5 larger reed
opening larger sound pressure
D6
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Summary

• An artificially blowing system was applied to the
  experimental examination of the vocal-tract
  effects on the clarinet altissimo tones. The
  resonance characteristics of our vocal-tract
  models yielded no appreciable differences in
  tones. Slight differences in spectral structure
  might be
• attributed to slight differences in reed
  opening.
• A much more precise adjustment of the resonance
  char-
• acteristics as well as the impedance
  measurement of the
• vocal-tract models should be needed to draw
  definite
• conclusions.

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Thank you for your attention.
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I.????

• ?????????
• ?????????(???????)
• ???????????
• ??????????????
• J.Backus(1963)
• T.A.Wilson(1974) ??
• ??????????????????
• A.H.Benade and P.L.Hoejke(1982)
• C.Fritz and J.Wolfe(2005) ??

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II.??

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