Operation Manual

6.12 Bowed Multimode 77
• Width: the width, in meters, of the membrane.
• Frequency: fundamental frequency, in Hertz, of the membrane when there is no pitch mod-
ulation signal or when its value is equal to 0. Note that the fundamental frequency is in-
dependent of the size of the membrane. The software automatically calculates the physical
parameters necessary to obtain the required fundamental frequency. The default value of
this parameter is 261.62 Hz which corresponds to the middle C (C3) of a piano keyboard.
This setting is convenient when controlling a Bowed Membrane module with a Keyboard
module.
• Decay: proportional to the decay time of the sound produced by the membrane.
• Number of Modes: number of modes used to simulate the object. As the number of modes
is increased, the number of partials in the sound increases but also inevitably the calculation
load.
• Excitation point-x: x-coordinate, in meters, of bow from the lower left corner of the mem-
brane.
• Excitation point-y: y-coordinate, in meters, of bow from the lower left corner of the mem-
brane.
• Listening point-x: x-coordinate, in meters, of listening point from the lower left corner of the
membrane. To obtain proper functioning, the excitation and listening points should be the
same.
• Listening point-y: y-coordinate, in meters, of listening point from the lower left corner of the
membrane. To obtain proper functioning, the excitation and listening points should be the
same.
Note: For more details on this module and especially the front panel controls, see the Bowed
Multimode module.
6.12 Bowed Multimode
The Bowed Multimode module is used by the Tassman to simulate mechanical objects such as
strings, plates, beams and membranes that are excited as a result of the interaction with a bow. The
output of this module is the acoustic signal that would be produced when these objects are bowed
and given a certain geometry, material, listening point and damping. The functioning of this module
is based on modal analysis. This technique is well-known in areas of physics and mechanics and is
used to describe complex vibrational motion using modes. Modes are just elementary oscillation
patterns that can be used to decompose a complex motion. By adding together modes having
different frequencies, amplitudes and damping, one can reproduce the behavior of different type
of structures. The accuracy of the resulting signal depends on the number of modes used in the
simulation.