Operation Manual

6.8 Beam 74
6.8 Beam
The Beam module simulates sound produced by beams of different materials and sizes. This
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 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 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 beam which shortens 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 beam itself. If this input is not connected to any other module, the default value
is set at 0, which implies that the beam 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 beam, the output from a Mallet module for example. The third input is a
pitch modulation signal.
Typical Use. See 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 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 impact point from the extremity of the beam.
• Listening point: x-coordinate, in meters, of listening point from the extremity of the beam.
Note: For more details on this module and especially the front panel controls, see the Multimode
module.