Proceedings of the Stockholm Music Acoustics Conference, August 6-9, 2003 (SMAC 03), Stockholm, Sweden
MEASUREMENT OF THE FORCE APPLIED TO THE MOUTHPIECE
DURING BRASS INSTRUMENT PLAYING
Jean-François PETIOT
Institut de Recherche en Communications et Cybernétique de Nantes (UMR CNRS 6597 - Equipe
MCM)- Ecole Centrale de Nantes, 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 3 France
[email protected]
ABSTRACT
In order to assess the load produced on the lips of the musician
during brass instrument playing, a measuring system was
developed. It permits the recording in real time of the axial force
created on the mouthpiece, and allows the players to perform on
their own instrument and mouthpiece, in their usual manner. Tests
involving 3 categories of players (professional – advanced –
beginners) were conducted with various musical phrases,
articulations and nuances. For all players, the force between the
mouthpiece and instrument always increases with increasing
loudness and ascending pitch, but in different proportions. After
an analysis of the causes of this force, the extent of these
variations is described and an interpretation of the results is
proposed. These measurements are particularly interesting for
musicians and physicist as well, in order to understand what the
control parameters of the embouchure are, and how to manage
them.
the diaphragm. The output is the acoustic pressure in the
mouthpiece, which generates a regime of oscillation in the
instrument.
Many parameters control this process. Firstly, the
instrument reacts on the lips of the musician, according to the
acoustic characteristics of the instrument body (mainly the
internal geometry or “bore”). The playing frequency of the note is
thus strongly attracted toward the resonance frequency of the
instrument [2]. Secondly, the musician can make vary the
characteristics of the tone by controlling the tension of the
muscles which position the lips. This is the crucial point of the
learning of brasses, and succeeding in this lips’ control can take
many years of hard practice. Finally, a third parameter control the
embouchure of the musician: the force applied by the mouthpiece
on the lips.
Control of the
muscles
1. INTRODUCTION
Wind instruments (with the exception of those with a flute-like
embouchure) are acoustic sources using a valve effect: the
acoustic oscillation is the result of a destabilisation of a
mechanical element whose movement changes the entrance crosssection of the instrument. This destabilisation is the result of a
complex aeroelastic coupling between the mechanical element
(the reed of a clarinet or the lips of a trombonist), the air flow
entering the instrument as a result of the static overpressure in the
mouth of the musician, and the instrument itself (the acoustic
resonator) [1].
In the case of brass instruments, the vibrations of the lips of
the musician are controlled both by the musician and the
instrument itself [2]. When we focus on the musician as a
“system”, several control parameters, which condition the natural
frequency of the lips, have to be considered (tension, geometry,
visco-elastic properties, ...). A great variety of musical sounds are
obtained by the control and the management in "real time" of
these parameters, this after several years of daily practice for the
musician.
Using a systemic approach, the embouchure of the musician
can be seen as a particular system, which performs a function, or
process, which results in an output. The block diagram of the
embouchure is described figure 1. This diagram shows the output,
input and control data of the system. The input is the static
overpressure in the mouth of the musician, created in the lungs by
Support
force
Static
overpressure
Acoustic
characteristics of the
instrument
Acoustic pressure
embouchure
Figure 1: Block diagram of the embouchure of a musician.
For all brass musicians, lips are a very sensitive area
because they are often hardly solicited. Every musician is
subjected to the phenomena of lips’ weakness, where it’s no
longer possible to play, and where a rest is necessary. This
phenomena is caused on the one hand by the fatigue of the
muscles of the embouchure, whose tension must always be
controlled, and on the other hand by the support of the
mouthpiece on the lips, which marks and traumatises the tissues.
All brass teachers agree on the fact that the force on the
mouthpiece must be as weak as possible, and various techniques
(“no pressing”) are developed so as to reduce its magnitude. But
this force exists at various degrees for several reasons:
- The force is necessary for the static airtightness between the
lips and the mouthpiece; it avoids the air from escaping
around the edges of the mouthpiece. This is inherent to the
way brass instruments are played, and for having airtightness,
the force cannot be nullified,
- The force can be used to modify the mechanical behaviour of
the lips. When one presses on the lips, the tissues becomes
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Proceedings of the Stockholm Music Acoustics Conference, August 6-9, 2003 (SMAC 03), Stockholm, Sweden
artificially more stiff, the mechanical characteristics of the
oscillator are then modified, and the regime of vibration of
the lips can be altered. In the same way, the variation of the
force can modify the boundary conditions of the lips, and can
eventually change the regime of vibration. We have clearly
observed this phenomena with artificial mouths, where an
increase of the force on the lips leads most of the time to a
modification of the played note [2].
The support force on the mouthpiece can thus be used so as to
compensate the inefficiency (or the fatigue) of the lips’ muscles.
This force can momentary overcome a lack of technique or an
excessive fatigue. But even if musicians are trained to carefully
control this force, all of them use it at various degrees during
playing.
Previous studies on the embouchure of the brass player have
specifically focused on the mouthpiece forces during playing. In
[3], recordings of the mouthpiece pressure and air pressure
variations by representative musicians are presented. For all
players, the mouthpiece pressure increases with the pitch of the
tones. A transducer for measuring the force applied to the
mouthpiece is described in [4]. This transducer gives both the
axial and sagittal forces created by the player on the mouthpiece.
The magnitude of the force was not significantly related to the
proficiency or playing style of the player. Another system, which
allows simultaneously the recording of mouthpiece forces and
teeth (incisor) deflection is proposed in [5]. Various brass
instruments was studied, and authors conclude that lip tension
must be responsible for the difference in teeth displacements, and
is of major importance in stressing the incisors during brass
instrument playing.
We present in this article some results of our experiments on
the study of the force created on the mouthpiece during brass
playing. In order to better know this phenomena, how it appears
and what are the influential factors, we developed a system for
the measurement of the force while playing a particular brass: the
fluegelhorn [6]. For recording purposes, the system was
connected to a PC based data acquisition system. We investigated
the influence on the magnitude of the force of factors like
proficiency, dynamic of the tone, articulation, pitch and duration
of the note, context of the note in the musical phrase.
2. EXPERIMENTAL STUDY
1.1. Description of the system
The measuring system has been adapted on a fluegelhorn, by
replacing the tuning slide of the instrument by a tube which can
glide freely in the mouthpipe. It is composed of the following
elements (see figure 2):
-
A tube, which glides in the instrument body,
A ring 1, clamped to the tube,
A ring 2, clamped to the instrument body,
-
A force captor (button load cells with strain
gauges), located between the rings. Range: 0 10daN, precision: 0.1%
Force captor
Instrument
body
Mouthpiece
Tube
Ring 1clamped
to the tube
Ring 2 clamped
to the body
Figure 2: Description of the force captor.
The force captor is glued to ring 2 and presses on ring 1.
When one presses on the mouthpiece, the axial force is directly
transmitted to the captor, the friction between the parts being
neglected. With this system, the measurement of the axial force
on the mouthpiece can be made under normal playing conditions:
the musician can use his/her usual performing technique while
measurements are made, and he/she is not very disturbed by the
system. The synoptic of the PC based data acquisition system is
presented figure 3.
Force captor
BC 302
Amplifier
ME52 AJ
Supplying
ME52AL26
±10V
A/D board
CIO-DAS08/Jr-AO
12bits
26Vdc
Graphs
Visualisation
Excel/Matlab
Acquisition
software
Labtech notebook
Figure 3: Synoptic of the acquisition system.
The measurement error is mainly due to the friction
between the tube and the body of the instrument, and the gap
between the position of the captor and the axis of the mouthpiece.
A mechanical modelling of the friction between the parts leads to
an estimation of this error of about 5%.
1.2. Experiments
Three brass musicians participated in the study. One was highly
proficient (professional), being full time professional player in
jazz big bands (5 hours per day); one was of advanced
proficiency (advanced), having at least 20 years of practice as
amateur (5 hours per week), and the last one of medium
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Proceedings of the Stockholm Music Acoustics Conference, August 6-9, 2003 (SMAC 03), Stockholm, Sweden
4,0
3,5
medium
3,0
advanced
2,5
force (daN)
proficiency (medium), with 5 years experience of the instrument
(2 hours per week). The musicians used their own mouthpiece
for the tests.
The tests consisted in playing successively an ascending
and descending two octaves arpeggio (with no valves operated) in
different style (staccato and legato), and different intensities
(mezzo forte, fortissimo). The tempo was around 60 per quarter
note for all tests.
professional
2,0
1,5
1,0
1.3. Results
Each musician performed several attempts. We did not represent
the average value of the force because it “smoothes” the curves,
and the time scale was not exactly the same for all attempts. Even
if the results presented concern particular tries, they are
representative of the behaviour of the musician. Figures 4, 5, 6, 7
present the magnitude of the mouthpiece force as a function of
time for various arpeggios and intensities.
0,5
0,0
0
1
2
3
4
5
6
7
8
time (s)
9
10
11
12
13
14
3,0
medium
2,5
advanced
ff
professional
force (daN)
2,0
Figure 6: force(time) for arpeggio 1, dynamic ff.
1,5
3,0
1,0
2,5
0,5
medium
advanced
professional
0
1
2
3
4
5
6
7
8
9
time (s)
10
11
12
13
14
15
force (daN)
2,0
0,0
1,5
1,0
0,5
0,0
m f
0
1
Figure 4: force(time) for arpeggio 1, dynamic mf.
2
3
4
5
6
7
8
time (s)
9
10
11
12
13
14
3,0
medium
advanced
professional
2,5
mf
force (daN)
2,0
Figure 7: force(time) for arpeggio 3, dynamic mf.
1,5
1,0
3. DISCUSSION
0,5
For all tests and all musicians, the magnitude of the force always
increases when the pitch of the note increases. This observation is
in accordance with the intuition, and with previous studies [3, 4,
5]. The magnitude of the force varies according to the proficiency
of our set of musicians. Higher is the level, weaker is the
maximum force.
We think that an intensive and regular practice of the
instrument leads to a sharp control of the playing parameters:
control of the embouchure, control of the air pressure and the air
flow. The “professional” musician use a force two or three time
0,0
0
1
2
3
4
5
6
7
8
time (s)
9
10 11 12 13 14 15
mf
Figure 5: force(time) for arpeggio 2, dynamic mf.
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Proceedings of the Stockholm Music Acoustics Conference, August 6-9, 2003 (SMAC 03), Stockholm, Sweden
less in average than the “medium” musician, and can in this way
increase the duration of playing without having rest.
The magnitude of the force increases with the intensity of
the tones (up to +20% from mf to ff). As the air pressure increase
with the intensity, an increasing of the force is necessary to
maintain the static airtightness between the lips and the
mouthpiece.
On figure 6, peaks in the force curve can be observed for
the “medium” musician. These peaks appear before each
changing of notes. The “medium” musician uses a brief increase
of the force for helping the changing of note. This behaviour is
typical of a musician who does not have a strong control of
his/her embouchure. In fact, among the playing parameters of the
fluegelhorn (control of the embouchure, control of the air
pressure and the air flow, control of the force on the mouthpiece),
a beginner will use the most instinctive and easiest controllable
parameter: the force on the mouthpiece. This phenomena, which
increases with the intensity of the notes, is absent for the
professional musician, who learned to change the note by
modifying the embouchure, mainly by pressing the lips vertically
against each others. Furthermore, the force generated by the
“medium” musician for the emission of a note is generally greater
than the force used for the sustain of this note (figure 6).
On figure 7, when notes are played separately, the
magnitude of the force between two notes decreases with the
proficiency of the musician. The “medium” musician keep on
pressing the mouthpiece even if no note is played. This point is of
major importance for having endurance and resistance during a
session.
For all musicians, the force used for notes played separately
is globally higher than the force needed for slurring notes. This
can be explained by the fact that the musician can control
continuously the parameters during slurred playing. Conversely,
for notes played separately, a continuous control of the parameter
is no longer possible, because no tone precedes the emission. A
increasing of the force could then be necessary so as to insure the
emission.
For all tests (figure 4, 5, 6, 7), force curves are not
symmetrical (at various degrees), whereas all musical phrases are
symmetrical. The tendency is that descending intervals need a
greater force than the same ascending intervals. The control of the
release of the embouchure and the air pressure during descending
intervals seems to be more difficult than the control of the
contraction (this is confirmed by many brass players). The
musician has recourse to an increasing of the force so as to insure
a descending interval.
have been made, with various musical phrases. We have
presented the results for three musicians of different proficiency.
The analysis of the measurements allows a better understanding
of the playing parameters of the fluegelhorn. The main result is
that the mouthpiece pressure was related, with our musicians, to
their proficiency. The mouthpiece pressure seems to be in many
case a substitute for muscular tension and embouchure control.
The device could be used by beginners to feel that this pressure is
undesirable when it takes over what muscular tension should do.
The findings have to be tested with large scale tests with several
subjects, in order to prove the significance of the observations
(statistical analysis).
5. ACKNOWLEDGMENTS
We acknowledge the help of Yannick Neveu, professional
trumpet player, for his participation.
6. REFERENCES
[1] Fletcher, N.H. and Rossing, T. D. “The physics of musical
Instruments”, Springer Verlag, New-York, 1991.
[2] Gilbert, J., Ponthus, S., Petiot, J.F., “Artificial buzzing lips
and brass instruments : experimental results”, J. Acoust. Soc.
Am. 104, 1627-1632, 1998.
[3] Henderson, H.W., “An experimental study of trumpet
embouchure”, J. Acoust. Soc. Am, Vol. 13, pp 58-64, 1942.
[4] Bardenel, J-C., “Mouthpiece forces produced while playing
the trumpet”, Journal of Biomechanics. Vol. 21, No.5, pp.
417-424, 1988.
[5] Borchers, L., Gebert, M., Jung, T., “Measurement of tooth
displacements and mouthpiece forces during brass
instrument playing, Med. Eng. Phys., Vol.17, No.8, pp 567570, 1995.
[6] Petiot, J-F. and Besnard, F., “Mesures de la force d’appui de
l’embouchure sur les lèvres lors du jeu des cuivres’, Revue
trimestrielle Médecine des Arts ISSN 1240-3784. N° 34 pp
7-9. December 2000.
4. CONCLUSIONS
We have presented in this paper a system for the measurement of
the force applied on the mouthpiece during brass instrument
playing. The system is easy to use and does not necessitate
complex modifications in the case of the fluegelhorn. We are
going to adapt the device to the trumpet. Several measurements
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