A disk drive is disclosed comprising a disk, an actuator arm, a head
connected to a distal end of the actuator arm, and a voice coil motor
(VCM) for rotating the actuator arm about a pivot to actuate the head
over the disk, wherein the VCM rotates the actuator arm into a latched
positioned when the disk drive is idle. Disk drive control circuitry
unlatches the actuator arm by applying a driving current to the VCM
according to an open-loop current profile. The open-loop current profile
comprises an acceleration pulse having an acceleration magnitude and an
acceleration interval, and a deceleration pulse having a deceleration
magnitude and a deceleration interval. The deceleration magnitude is
substantially smaller than the acceleration magnitude, and the
deceleration interval is substantially longer than the acceleration
interval, to thereby attenuate acoustic noise when unlatching the
actuator arm.