7.5 Going Further: Trumpets and Cornets—Are They Different?
371
instrument is of minor importance. A simple experiment is to extend the stem of
a mouthpiece with a roll of paper: a small increase in backbore length audibly
lowers the popping frequency. The popping frequency of a detached mouthpiece
can give an approximate indication of the region of resonance boost, but although it
is readily measurable, it is not a reliable parameter for comparative taxonomy. The
cup volume, although more difficult to measure, provides a more robust parameter.
In defining the cup volume as a taxonomic parameter we sometimes disregard the
protrusion of a player’s lips into the cup when playing, as it is highly variable (and
under the control of the player to some extent). We also need to establish where the
cup ends and the backbore begins. Although this is necessarily somewhat artificial,
it is not of critical importance as the throat is much narrower than the cup diameter,
and any error determining the position of the bottom of the cup will have a relatively
small effect. Cup volume can be measured by blocking the throat and filling the
cup with water, or it can be computed from physical measurements. In Sect. 7.7 we
employ the latter method, since physical measurements also allow us to characterise
the shape of the cup.
The listener’s perception of timbre depends not only on the steady state spectrum
of the sustained sound, but also on the starting transient. Cup shape, especially the
shape of the throat where the bottom of the cup leads into the minimum bore, seems
likely to affect transients even if steady state sound is largely independent of cup
shape detail. Some players consider that throat curvature affects the response of the
system to the ‘attack’ of a note—the ease for the player of commencing a note and
the heard starting transient. When air flows from the cup though the throat into the
minimum bore (‘grain’) past the sharp edge as in hemispherical cup mouthpieces,
flow separation occurs, with toroidal vortices inside the throat. These absorb some
of the energy, and reduce the effective cross-sectional area of the throat (Vereecke
and Carter 2014). Mouthpiece aerodynamics is a topic very ripe for further research.
Players are extremely sensitive to small changes in mouthpiece shape, whether
changes to the rim and bite affecting the placement of the mouthpiece on the lips
or changes to the cup, throat and backbore affecting air flow. The material of
construction is possibly also a factor: most mouthpieces are metal, but ivory, wood
and plastic have also been used. Changes detectable by a skilled player can be too
small and too diverse to be easily explained in scientific terms (see Sect. 6.6.5).
7.5 Going Further: Trumpets and Cornets—Are They
Different?
The difference between trumpets and cornets is often a source of confusion. Part of
the problem is that what has been meant by the terms ‘Cornet’ and ‘Trumpet’ has
differed from decade to decade and from country to country. Even at one time and in
one place, the names used by instrument makers, players, composers and arrangers
371
instrument is of minor importance. A simple experiment is to extend the stem of
a mouthpiece with a roll of paper: a small increase in backbore length audibly
lowers the popping frequency. The popping frequency of a detached mouthpiece
can give an approximate indication of the region of resonance boost, but although it
is readily measurable, it is not a reliable parameter for comparative taxonomy. The
cup volume, although more difficult to measure, provides a more robust parameter.
In defining the cup volume as a taxonomic parameter we sometimes disregard the
protrusion of a player’s lips into the cup when playing, as it is highly variable (and
under the control of the player to some extent). We also need to establish where the
cup ends and the backbore begins. Although this is necessarily somewhat artificial,
it is not of critical importance as the throat is much narrower than the cup diameter,
and any error determining the position of the bottom of the cup will have a relatively
small effect. Cup volume can be measured by blocking the throat and filling the
cup with water, or it can be computed from physical measurements. In Sect. 7.7 we
employ the latter method, since physical measurements also allow us to characterise
the shape of the cup.
The listener’s perception of timbre depends not only on the steady state spectrum
of the sustained sound, but also on the starting transient. Cup shape, especially the
shape of the throat where the bottom of the cup leads into the minimum bore, seems
likely to affect transients even if steady state sound is largely independent of cup
shape detail. Some players consider that throat curvature affects the response of the
system to the ‘attack’ of a note—the ease for the player of commencing a note and
the heard starting transient. When air flows from the cup though the throat into the
minimum bore (‘grain’) past the sharp edge as in hemispherical cup mouthpieces,
flow separation occurs, with toroidal vortices inside the throat. These absorb some
of the energy, and reduce the effective cross-sectional area of the throat (Vereecke
and Carter 2014). Mouthpiece aerodynamics is a topic very ripe for further research.
Players are extremely sensitive to small changes in mouthpiece shape, whether
changes to the rim and bite affecting the placement of the mouthpiece on the lips
or changes to the cup, throat and backbore affecting air flow. The material of
construction is possibly also a factor: most mouthpieces are metal, but ivory, wood
and plastic have also been used. Changes detectable by a skilled player can be too
small and too diverse to be easily explained in scientific terms (see Sect. 6.6.5).
7.5 Going Further: Trumpets and Cornets—Are They
Different?
The difference between trumpets and cornets is often a source of confusion. Part of
the problem is that what has been meant by the terms ‘Cornet’ and ‘Trumpet’ has
differed from decade to decade and from country to country. Even at one time and in
one place, the names used by instrument makers, players, composers and arrangers