A method and apparatus for detecting the connection of an external audio accessory to an audio device via a two-wire audio jack includes providing a DC bias on the output of the audio circuit connected to the audio jack. The audio jack is such that, when a plug is inserted into the audio jack, the DC bias is removed from an internal routing pin of the audio jack. The change in DC voltage at the internal routing pin indicates connection of the external audio accessory. Furthermore, upon detection, the AC response of the external audio accessory can be determined, and used to select a set of audio settings to be applied to the audio components of the audio device to optimize the performance of the external audio accessory.