azimuth

The azimuth property moves sound around the listener. It provides a way to tell several voices apart, as in real life (people rarely all stand in the same spot in a room). In an optimal listening environment, the soundstage is considered to be parallel to the floor, with origin point at the listener's head. The ideal listening position is considered to be facing the main sound reproduction source at an optimal distance.

Stereo speakers produce a lateral sound stage. Some headphones or stereos and televisions can generate surround sound.

You specify it as an angle in degrees (between -360° and 360°). For example:

P  {azimuth: 0deg}
h1 {azimuth: 30deg}

The value 0deg is straight ahead of the listener. Positive value move clockwise around the listener; negative values move anticlockwise. So, 90deg is to the right, 180deg directly behind, and 270deg to the left.

You can also specify a keyword. For example:

P  {azimuth: far-right}
p  {azimuth: behind far-right}
P  {azimuth: behind}

Each of the keywords corresponds to an angle. You have the following options:

left-side (270deg). If you also specify behind, this is -90deg
far-left (300deg). If you also specify behind, this is 240deg
left (320deg). If you also specify behind, this is 220deg
center-left (340deg). If you also specify behind, this is 200deg
center (0deg). If you also specify behind, this is 180deg
center-right (20deg). If you also specify behind, this is 160deg
Right (40deg). If you also specify behind, this is 140deg
far-right (60deg). If you also specify behind, this is 120deg
right-side (90deg). If you also specify behind, this is 90deg

You can also enter relative values leftwards and rightwards:

Leftwards. Moves the sound to the left of the current angle. (It subtracts 20 degrees from the current angle). This means the sound turns anti-clockwise because the browser always subtracts 20 degrees, even if the azimuth is already behind the listener (in which case the sound actually appears to move to the right)
Rightwards. Moves the sound to the right of the current angle. (It adds 20 degrees from the current angle). The sound turns clockwise

Remember that as you in increase or decrease the elevation, the azimuth is less apparent to the listener. For example, if a sound is directly overhead, you can't tell if it is in front of you or behind you.