post {protocol}://api.ws.sonos.com/control/api/{version}/players//playerVolume
Use the setVolume command to set the player's volume and mute state.
Returns an empty body with a success value of true if successful. The player generates a playerVolume event if the volume was changed.
Additionally, if setVolume is called on a player that has a fixed player volume state that is true, the command will fail and you will receive an ERROR_COMMAND_FAILED globalError. This is because players with fixed volumes cannot be changed, for example, a CONNECT with fixed line out would respond with this error if your app tried to set the volume on it.