3.1 The Nature of Lip Vibration
77
Fig. 3.15 An artificial mouth for sounding brass instruments. Left view: fitted with a transparent
mouthpiece for high-speed filming. Right view: fitted with a conventional trombone mouthpiece
with an optional shunt hole in the backbore (Richards 2003)
Gilbert et al. 1998; Cullen 2000; Ehara et al. 2001; Bromage et al. 2003; Petiot
et al. 2003; Vilain et al. 2003). An artificial mouth using latex lips is illustrated in
Fig. 3.15.
It is evident that an artificial embouchure using cylindrical latex tubing is
incapable of reproducing fully the complex behaviour of the human embouchure
described in Sect. 3.1.1. The artificial lips are therefore only of passing interest to
the musician. From the scientific perspective, however, it is very valuable to be able
to study the physics of artificial lips, since despite their simplicity they are capable of
generating musically acceptable sounds on brass instruments. Many aspects of the
complicated relationship between the player and the instrument have been clarified
by experiments using artificial mouths.
Figure 3.16 illustrates the nature of the lip motion recorded using a high-speed
camera when the artificial mouth sounded the note F3 on a tenor trombone using the
transparent mouthpiece shown in Fig. 3.3. The sequence of nine images in Fig. 3.16
shows just over one cycle of opening and closing of the aperture between the lips.
The variation of open area is similar to that seen when a human player plays the
same pitch.
Figure 3.17 shows measurements of the trajectory in the yz plane of a fixed
point near the centre of the upper artificial lip when the note F3 was sounded on a
tenor trombone (Richards 2003). These measurements were carried out using a highspeed camera which could be rotated to different viewing angles, taking advantage
of the long-term stability of the artificial lip excitation. The note was played at a
musical forte level, corresponding roughly to the ‘loud’ dynamic level generated
by the human player whose lip trajectories were measured by Copley and Strong
(Sect. 3.1.5). The curve for the note F3 in Fig. 3.14 has some similarities with the
artificial lip trajectory in Fig. 3.17. In both cases the motion near the tip of the upper
lip, starting from the point at which y = 0, can be thought of as outward and upward,
then backward and downward, with a final forward motion to the point of minimum
transverse displacement. In each case the maximum transverse (y) displacement is
significantly larger than the maximum axial (z) displacement. However the shapes
of the trajectories are noticeably different, and the displacements of the human lip
are around 50% greater than the corresponding displacements of the artificial lip.
77
Fig. 3.15 An artificial mouth for sounding brass instruments. Left view: fitted with a transparent
mouthpiece for high-speed filming. Right view: fitted with a conventional trombone mouthpiece
with an optional shunt hole in the backbore (Richards 2003)
Gilbert et al. 1998; Cullen 2000; Ehara et al. 2001; Bromage et al. 2003; Petiot
et al. 2003; Vilain et al. 2003). An artificial mouth using latex lips is illustrated in
Fig. 3.15.
It is evident that an artificial embouchure using cylindrical latex tubing is
incapable of reproducing fully the complex behaviour of the human embouchure
described in Sect. 3.1.1. The artificial lips are therefore only of passing interest to
the musician. From the scientific perspective, however, it is very valuable to be able
to study the physics of artificial lips, since despite their simplicity they are capable of
generating musically acceptable sounds on brass instruments. Many aspects of the
complicated relationship between the player and the instrument have been clarified
by experiments using artificial mouths.
Figure 3.16 illustrates the nature of the lip motion recorded using a high-speed
camera when the artificial mouth sounded the note F3 on a tenor trombone using the
transparent mouthpiece shown in Fig. 3.3. The sequence of nine images in Fig. 3.16
shows just over one cycle of opening and closing of the aperture between the lips.
The variation of open area is similar to that seen when a human player plays the
same pitch.
Figure 3.17 shows measurements of the trajectory in the yz plane of a fixed
point near the centre of the upper artificial lip when the note F3 was sounded on a
tenor trombone (Richards 2003). These measurements were carried out using a highspeed camera which could be rotated to different viewing angles, taking advantage
of the long-term stability of the artificial lip excitation. The note was played at a
musical forte level, corresponding roughly to the ‘loud’ dynamic level generated
by the human player whose lip trajectories were measured by Copley and Strong
(Sect. 3.1.5). The curve for the note F3 in Fig. 3.14 has some similarities with the
artificial lip trajectory in Fig. 3.17. In both cases the motion near the tip of the upper
lip, starting from the point at which y = 0, can be thought of as outward and upward,
then backward and downward, with a final forward motion to the point of minimum
transverse displacement. In each case the maximum transverse (y) displacement is
significantly larger than the maximum axial (z) displacement. However the shapes
of the trajectories are noticeably different, and the displacements of the human lip
are around 50% greater than the corresponding displacements of the artificial lip.