Select the listener's orientation:
Orientations are for a listener sitting at the Earth's center looking out. Azimuth 0° means facing out towards the Greenwich meridian. Azimuth increases eastward (towards the listener's left). For example, an azimuth of +45° is at the listener's left-front, corresponding to longitude 45E (near Mogadishu). An azimuth of -165° would be almost directly behind the listener, slightly to the right (longitude 165W; near Kiribati in the South Pacific).
Pitch and Roll are not yet implemented. This calculator assumes that the listener is oriented such that the North-South polar axis is parallel to the listener's median plane and normal to the listener's transverse plane. I.e., the North Pole is directly overhead and the South Pole is directly under your feet.
For the PHP source code, please contact me.