Apparatus and method for triggering a centering of a head-tracking system on a head-worn wearable device

A computer program product embodied in a non-transitory computer readable medium that is programmed for determining relative orientation of headphones, the computer-program product comprising instructions and being executable by at least one processor for:

• receiving a first signal indicative of a command to establish a relative orientation for the headphones from a switch to establish the relative orientation of the headphones;
• receiving a second signal indicative of movement of the headphones relative to a user's head;
• determining that the headphones are in a stable state after moving relative to the user's head;
• and
• establishing the relative orientation of the headphones while positioned on the user's head in response to at least determining that the headphones are in the stable state.

A headphone assembly comprising:

• headphones;
• at least one motion detector configured to transmit a first signal indicative of movement of the headphones;
• and
• at least one processor programmed to:
• determine that the headphones are on a user's head;
• and
• establish a relative orientation of the headphones while positioned on the user's head as a frame of reference for subsequent relative orientation measurements in response to at least determining that the headphones are in a stable state while being worn by the user and after the determining that the headphones are on the user's head.