Operation Manual

6.63 Plectrum 123
6.63 Plectrum
The Plectrum module is used to simulate the excitation of a string when it is
plucked by a finger or a pick. The output of this module is the force signal applied
by the plectrum on the string. Before a string starts to vibrate, the plectrum moves
the string. A force is supplied to the string while the plectrum and the string are in
contact. The shape of the force signal is dependent on the stiffness of the plectrum
which can be adjusted with the stiffness knob. The harder the pick, the sharper the
force signal while a soft plectrum results in a smoother signal. The amplitude of
this force signal is adjusted with the strength knob.
This module has four inputs. The first input triggers the plectrum every time a low-to-high
transition is encountered in the input signal. This input is usually connected to the gate signal
from a Keyboard module. Note that the Plectrum can also be triggered manually by using the
trig button on the front panel. The second input signal modulates the stiffness of the plectrum
relative to the value selected with the stiffness knob. The amplitude of the modulation is adjusted
with the mod1 gain knob. The greater the amplitude, the greater the stiffness. This modulation
input is used, for example, when a variation of the stiffness of the plectrum with the note played is
desired. When the knob is adjusted in its center position and when this input 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 of the second input which implies that the stiffness
decreases when the input signal increases. This input is usually connected to the velocity output
from a keyboard module which implies that the plectrum softens as the impact velocity increases.
The amplitude of this input is adjusted with the mod2 gain knob. The last input modulates the
amplitude of the force signal relative to the adjustment of the strength knob. This input is also
generally connected to a velocity signal in order to increase the amplitude of force supplied by the
plectrum with the velocity signal. The amplitude of this modulation signal is adjusted with the
mod3 gain knob.
Typical Use
A Plectrum can be used to excite a String module as in the following example.
Figure 69: A Plectrum module exciting a String.