guiro is a semi-physical model of a guiro sound. It is one of the PhISEM percussion opcodes. PhISEM (Physically Informed Stochastic Event Modeling) is an algorithmic approach for simulating collisions of multiple independent sound producing objects.
idettack -- period of time over which all sound is stopped
inum (optional) -- The number of beads, teeth, bells, timbrels, etc. If zero, the default value is 128.
idamp (optional) -- the damping factor of the instrument. Not used.
imaxshake (optional, default=0) -- amount of energy to add back into the system. The value should be in range 0 to 1.
ifreq (optional) -- the main resonant frequency. The default value is 2500.
ifreq1 (optional) -- the first resonant frequency.
kamp -- Amplitude of output. Note: As these instruments are stochastic, this is only an approximation.