Operation Manual

6.40 Marimba 102
is connected to a pitch signal, the stiffness exactly follows the pitch variation so as to ensure that
the spectral content (or color) of the sound produced by a structure is uniform when the pitch is
varied. The third input also modulates the stiffness, but in the reverse manner as for the second
input so that the stiffness of the mallet decreases when the input signal increases. This input is
usually connected to the velocity output from a keyboard module which implies that the mallet will
soften as the impact velocity increases. This is a behavior one observes, for example, on piano
hammer heads due to the non-linearity of the felt. The amplitude of this input is adjusted with the
mod2 gain knob. The last input modulates the strength of the impact relative to the adjustment of
the strength knob. This input is also generally connected to a velocity signal so as to increase the
force of the impact with the velocity signal. The amplitude of this modulation signal is adjusted
with the mod3 gain knob.
Typical Use
A Mallet module is generally used to excite Multimode objects such as Beams, Membranes,
Strings and Plates. See the example in Figure 58 under Multimode.
The default value of the following parameters is set at construction
• Strength: default value of the impact force (value between 0 and 2).
• Stiffness: default value of mallet stiffness (value between 1 and 20 000).
Note: see also Noise Mallet.
6.40 Marimba
The Marimba module simulates sound production by marimba bars of different material and sizes.
This module reproduces the characteristic tuning of marimba bars overtones obtained with the
deep arch-cut of the bars. This module, which constitutes a special case of the Beam module,
first calculates the modal parameters corresponding to marimba bar shaped objects according to
the value of the different parameters requested at construction time and, next, calls the Multimode
module to simulate the sound. The module has one output, the sound produced by the marimba bar,
and three inputs. The first input signal is a damping signal which, depending on its value, lowers
or raises dampers on the structure. When the input signal is equal to 0, dampers are lowered on
the bar, thus shortening the decay time of the sound produced by the structure. When the signal
is greater than 0, dampers are raised. Note that this damping adds to the natural damping of the
marimba bar itself. If this input is not connected to any other module, the default value is set at
0, which implies that the marimba bar motion will be damped. This input is, therefore, usually
connected to a Constant module to obtain undamped motion or to a Damper module or the gate
signal from a keyboard in order to vary the damping while playing. The second input signal is the
force signal exciting the marimba bar, while the third is a pitch modulation signal.