54
2 The Scientist’s Perspective on Brass Instrument Behaviour
0
200
400
600
800
1000
1200
1400
1600
Frequency (Hz)
0
200
400
600
Amplitude (arb. units)
0
200
400
600
800
1000
1200
1400
1600
Frequency (Hz)
0
20
40
60
80
100
120
Input impedance (megohms)
0
200
400
600
800
1000
1200
1400
1600
Frequency (Hz)
0
20
40
60
80
Amplitude (arb. units)
(a)
(b)
(c)
Fig. 2.18 (a) Frequency spectrum of trumpet note F4. (b) Input impedance curve for a B trumpet.
Green lines: harmonics of F4. Red lines: harmonics of B 2. (c) Frequency spectrum of trumpet note
B 2 (pedal note) (Color figure online)
corresponding requirement of an approximately harmonic set of resonances as the
‘Bouasse-Benade prescription’ (see Sect. 5.4.5).
Figure 2.18c shows the frequency spectrum for the note B 2 played on the
trumpet. This ‘pedal note’ is difficult to sound in tune, because there is no acoustic
resonance to support the first harmonic of the mouthpiece pressure. There is
however the possibility of support for the higher harmonics, each of which lies not