The variations in intensity of the middle portion of the ENVELOPE of a SOUND OBJECT, between its ATTACK and DECAY. These internal dynamics may remain nearly stationary in simple sounds, or in complex sounds may include secondary attacks, growths and decays between the initial attack and the final decay.
See: GRAIN, STATIONARY SOUND, STATIONARY STATE, TRANSIENT. Compare: DRONE, HUM, MODULATION, STOCHASTIC PROCESS.
Sound Example: Power line hum with internal dynamics.Sound Example: Spinning wheel.