User Manual

ARTURIA – BRASS 2 – USER’S MANUAL
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simultaneously: thus the resonance frequency of a trumpet with all pistons held
down is three steps lower (0.5+1.0+1.5) than a trumpet with all the pistons
released.
By playing notes in these two ways, it is possible for the trumpeter to play all the notes
of the chromatic scale. It is the same when you play a note in BRASS 2; it is good that
one or the other of these options is put into place by the model.
8.1.1.3 Brassy sounding… Brass!
One of the essential characteristics in the performance of brass instruments is their
ability to transform and enrich the harmonic content produced when the volume level
augments. We’re talking about a metallic, bright, or even brassy sound. This
transformation of sound is principally due to the progressive distortion of acoustic waves
as they spread into the body of an instrument. The phenomenon is similar to the
formation of ocean waves, nearly winding in high tides, and that progressively crash into
one another while approaching the shore until surging and breaking onto the beach. The
equivalent of crashing for acoustic waves is the formation of shock waves in the interior
of the instrument. It is this spectacular distortion of pressure waves that is identified by
the ear and associated with a brass sound. To experience this with BRASS 2, breathe
stronger and stronger by increasing the “pressure” parameter and listen: the sound is
not only louder, it is also richer and colorful, in effect…brassy!
8.1.2 Trombone
The functioning of the trombone is very similar to that of the trumpet. The main
difference is that while a trumpeter is limited to a finite number of ways to elongate his
instrument (only 8 possible positions) the trombonist has a nearly-infinite range of
possibilities by setting the position of the slide at will.
One of the playing techniques unique to the trombone is due precisely to the possibilities
offered by means of the slide; the trombone can play a glissando like no other. Imagine
for example that the musician wishes to perform an ascending glissando: starting with a
precise note, progressively shorten the length of the instrument (and thus increase the
resonance frequency) by pulling the slide inward. But this is not enough! As we have said
for the trumpet, the sound frequency is influenced by the resonance frequency of the
instrument and lips. Thus, the trombonist must increase the resonance frequency of his
lips at the same time that he is moving the slide. This technique is very delicate and
takes a lot of work to master with the real instrument, but luckily, the technique is put at
the disposition of all BRASS 2 users in an easily accessible way.
8.2 Technology used with the Trumpet and Trombone
The trumpet and trombone models were developed by the researchers at IRCAM who
based all experiments on experience with real instruments. Through a few examples we
will see how the models used in BRASS 2 benefit from the most recent research in
musical acoustics.
8.2.1.1 The acoustic signature of the instrument
In order to define instrumental behavior, measures of acoustic impedance and impulse
response in an anechoic chamber were performed. This method acts as a precise
measure of the echo produced by a trumpet in response to an acoustic impulse: It is in
some way as though we shot a rifle in a room in the form of a trumpet or trombone and
saved the echo or reverberation returned by the room. The impulse response on an
instrument is made up of its acoustic signature and is an integral part of the physical
model used in BRASS 2.