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6.9 Bowed Beam 71
6.9 Bowed Beam
The Bowed Beam module simulates sound produced by bowed beams of different materials and
sizes. This module first calculates the modal parameters corresponding to beam shaped objects
depending on the value of the different parameters requested at construction time and, next, calls
the Bowed Multimode module to simulate sound production by the beam. The module has one
output, the sound produced by the beam, and three inputs. The first input signal is the bow velocity
in the direction of the motion. The second input signal is a force signal which is considered to act
perpendicularly to the motion of the beam. The third input is a pitch modulation signal.
Typical Use. See Bowed Multimode module.
The default value of the following parameters is set during construction
•
Length: the length, in meters, of the beam.
•
Frequency: fundamental frequency, in Hertz, of the beam when there is no pitch modulation
signal or when its value is equal to 0. Note that the fundamental frequency is independent
of the length of the beam. 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 Beam module with a Keyboard module.
•
Decay: proportional to the decay time of the sound produced by the beam. 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-coordinate, in meters, of bow from the extremity of the beam.
•
Listening point: x-coordinate, in meters, of listening point from the extremity beam. 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.
6.10 Bowed Marimba
The Bowed Marimba module simulates sound produced by bowed marimba bars of different
materials 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
Bowed Beam module first calculates the modal parameters corresponding to beam-shaped objects
according to the value of the different parameters requested at construction time and, next, calls the
Bowed Multimode module to simulate sound production by the bars. The module has one output,
the sound produced by the beam, and three inputs. The first input signal is the bow velocity in