A portable electronic device, such as a pager or a mobile station, has a housing and a vibration motor coupled to the housing for imparting vibration to it. Within the device, an electronic audio signal is preferably split into high and low frequency components by parallel filters. Pulses of the low frequency component are rectified, voltages of those rectified pulses are quantified and at least some are converted to pulse widths, and the train of pulse widths is amplified to drive the vibration motor, resonating the housing at in correspondence with the pulse amplitudes of at least some pulses of the original electronic audio signal. Various adaptive schemes are presented to control the number of modulated pulses that drive the vibration motor to enhance the user experience. The vibration motor may act as an audible sub-woofer and/or may provide a bass effect vibration within or beyond the audible range in correspondence to certain spaced pulses of the original audio signal.