A tactile input to a system having a speaker located in an enclosure with an audio port can be detected by generating a sound wave in response to a signal and sensing the phase relationship between the current phase and the voltage phase of the signal. While the audio port is open a baseline current and voltage phase difference is established. When the audio port is obstructed by a finger touch, the current and voltage phase difference is altered in response to the obstruction. While the altered phase difference is detected, a tactile event is indicated.