7.1 What Are Important Features of Brass Instruments?
339
where c is the speed of sound (see Sect. 4.3.4). Values of L ecN are calculated from
Eq. 7.1 with c = 346 m s −1 , a typical figure for air inside wind instruments. The
instruments are taken to have toneholes all covered, slides in closed position, and
no keys or valves operated.
The nominal equivalent cone length can differ significantly from the physical
length of the instrument tubing, depending on the bore profile and the assumed
pitch standard. It should also be noted that the value of L ecN does not necessarily
agree exactly with the distance in feet specified in the pitch label. For example, the
nominal equivalent cone length for a trumpet in ‘4-ft C’ is given in Table 7.1 as
L ecN = 1.32 m: this is 10 cm longer than four feet (1.22 m). The nominal pitch label
must therefore be considered as defining a category rather than a specific length.
7.1.2 Bore Profile and Brassiness
Once the basic necessities of sufficiently inflexible tubing, a stable structure and
manageable wrap and ergonomics have been provided, the most important design
features which instrument designers control are those of bore profile. The bore
profile is the principal determinant of an instrument’s compass, dynamic range,
timbre, responsiveness, and to some extent intonation control. It is the bore profile
which makes a B trumpet different from a B flugelhorn and a tenor valve trombone
different from a euphonium. It is also the finer details of bore profile which largely
distinguish the different models of instrument a maker will offer, the instruments
of one maker from those of another, and good instruments from bad. This was
realised in the middle of the nineteenth century; for example, the inventor and maker
Adolphe Sax wrote (Sax 1850):
Proportions are the governing laws and constitute the nature of the instrument; indeed it
is not the form that gives them their voice, their sound quality: it is only the proportions.
These proportions are, therefore, different for each species of instrument.
The design of the mouthpiece is an integral part of the design of a brass
instrument; however the mouthpiece has specific acoustical functions, and as the
interface between instrument and player is of critical importance on several counts.
Although instrument makers often include a mouthpiece when they supply an
instrument, players usually make a separate choice and will often use a single
mouthpiece to play different instruments. For these reasons it is helpful to consider
instrument taxonomy and mouthpiece taxonomy separately (see Sect. 7.4).
The bore profile of an instrument can be infinitely varied by the designer,
and a complete description using a small number of parameters is impossible.
In Sects. 4.3 and 6.1 we discussed the effects of bore size (tube diameter) and
nonlinear propagation (brassiness) on timbre. The values of the two parameters D min
and B effectively determine much of the nature of an instrument of a given tube
length. The timbre of an instrument depends of course on playing technique and
mouthpiece choice, but together D min and B largely characterise the contribution of
339
where c is the speed of sound (see Sect. 4.3.4). Values of L ecN are calculated from
Eq. 7.1 with c = 346 m s −1 , a typical figure for air inside wind instruments. The
instruments are taken to have toneholes all covered, slides in closed position, and
no keys or valves operated.
The nominal equivalent cone length can differ significantly from the physical
length of the instrument tubing, depending on the bore profile and the assumed
pitch standard. It should also be noted that the value of L ecN does not necessarily
agree exactly with the distance in feet specified in the pitch label. For example, the
nominal equivalent cone length for a trumpet in ‘4-ft C’ is given in Table 7.1 as
L ecN = 1.32 m: this is 10 cm longer than four feet (1.22 m). The nominal pitch label
must therefore be considered as defining a category rather than a specific length.
7.1.2 Bore Profile and Brassiness
Once the basic necessities of sufficiently inflexible tubing, a stable structure and
manageable wrap and ergonomics have been provided, the most important design
features which instrument designers control are those of bore profile. The bore
profile is the principal determinant of an instrument’s compass, dynamic range,
timbre, responsiveness, and to some extent intonation control. It is the bore profile
which makes a B trumpet different from a B flugelhorn and a tenor valve trombone
different from a euphonium. It is also the finer details of bore profile which largely
distinguish the different models of instrument a maker will offer, the instruments
of one maker from those of another, and good instruments from bad. This was
realised in the middle of the nineteenth century; for example, the inventor and maker
Adolphe Sax wrote (Sax 1850):
Proportions are the governing laws and constitute the nature of the instrument; indeed it
is not the form that gives them their voice, their sound quality: it is only the proportions.
These proportions are, therefore, different for each species of instrument.
The design of the mouthpiece is an integral part of the design of a brass
instrument; however the mouthpiece has specific acoustical functions, and as the
interface between instrument and player is of critical importance on several counts.
Although instrument makers often include a mouthpiece when they supply an
instrument, players usually make a separate choice and will often use a single
mouthpiece to play different instruments. For these reasons it is helpful to consider
instrument taxonomy and mouthpiece taxonomy separately (see Sect. 7.4).
The bore profile of an instrument can be infinitely varied by the designer,
and a complete description using a small number of parameters is impossible.
In Sects. 4.3 and 6.1 we discussed the effects of bore size (tube diameter) and
nonlinear propagation (brassiness) on timbre. The values of the two parameters D min
and B effectively determine much of the nature of an instrument of a given tube
length. The timbre of an instrument depends of course on playing technique and
mouthpiece choice, but together D min and B largely characterise the contribution of