66
3 Buzzing Lips: Sound Generation in Brass Instruments
Fig. 3.3 Transparent
mouthpiece used for
high-speed video recording of
in plane lip motion during
trombone playing
sequences of images of a cornet player’s lips at different stages in a cycle of
vibration. Similar techniques have subsequently been used by various researchers to
study the motion of lips in the mouthpieces of horns (Yoshikawa 1995; Yoshikawa
and Muto 2003) and trombones (Copley and Strong 1996; Richards 2003; Bromage
2007; Boutin et al. 2015b).
A transparent trombone mouthpiece specially designed to allow the open area
between the lips to be clearly visualised is shown in Fig. 3.3. In this mouthpiece,
based on a design by Ayers (1998, 2001), the stem connecting the cup to the
instrument is at right angles to the blowing direction, and a flat window at the base
of the cup allows the lips to be viewed from the front. The cup volume and rim
diameter are similar to those of a Denis Wick 6BS trombone mouthpiece.
The use of a high-speed camera to record the motion of a brass player’s lips
during playing was discussed briefly in Sect. 2.1.4. Figure 3.4 illustrates the nature
of the lip motion recorded by Bromage et al. (2010) when a trombone player
sounded the pedal note B 1, with a frequency of 58.3 Hz, using the mouthpiece
shown in Fig. 3.3. The sequence of 14 images in Fig. 3.4, reading from top to bottom
in the left-hand column and then from top to bottom in the right-hand column, shows
the gradual closing and then re-opening of the aperture between the lips during one
cycle of the vibration. The time interval between successive images was 1.32 ms, so
that the complete cycle was recorded in 17.2 ms.
3.1.3 Time Dependence of the Lip Opening Area
In describing the motion of the lips, it is helpful to make use of the rectilinear
co-ordinate system shown in Fig. 3.5. The z axis is the direction of flow of air
through the lip opening; the x axis lies along the mid-line between the lips when
3 Buzzing Lips: Sound Generation in Brass Instruments
Fig. 3.3 Transparent
mouthpiece used for
high-speed video recording of
in plane lip motion during
trombone playing
sequences of images of a cornet player’s lips at different stages in a cycle of
vibration. Similar techniques have subsequently been used by various researchers to
study the motion of lips in the mouthpieces of horns (Yoshikawa 1995; Yoshikawa
and Muto 2003) and trombones (Copley and Strong 1996; Richards 2003; Bromage
2007; Boutin et al. 2015b).
A transparent trombone mouthpiece specially designed to allow the open area
between the lips to be clearly visualised is shown in Fig. 3.3. In this mouthpiece,
based on a design by Ayers (1998, 2001), the stem connecting the cup to the
instrument is at right angles to the blowing direction, and a flat window at the base
of the cup allows the lips to be viewed from the front. The cup volume and rim
diameter are similar to those of a Denis Wick 6BS trombone mouthpiece.
The use of a high-speed camera to record the motion of a brass player’s lips
during playing was discussed briefly in Sect. 2.1.4. Figure 3.4 illustrates the nature
of the lip motion recorded by Bromage et al. (2010) when a trombone player
sounded the pedal note B 1, with a frequency of 58.3 Hz, using the mouthpiece
shown in Fig. 3.3. The sequence of 14 images in Fig. 3.4, reading from top to bottom
in the left-hand column and then from top to bottom in the right-hand column, shows
the gradual closing and then re-opening of the aperture between the lips during one
cycle of the vibration. The time interval between successive images was 1.32 ms, so
that the complete cycle was recorded in 17.2 ms.
3.1.3 Time Dependence of the Lip Opening Area
In describing the motion of the lips, it is helpful to make use of the rectilinear
co-ordinate system shown in Fig. 3.5. The z axis is the direction of flow of air
through the lip opening; the x axis lies along the mid-line between the lips when