Swapping left and right channels in a stereo pair
Tap the “Rooms” tab.
Tap the Pencil 
icon to enter Edit mode.
icon to enter Edit mode.Tap a Stereo Pair (a room which contains two matching speakers) to edit the group.
Tap on the Swap L&R switch to swap the left and right channels of the two speakers.
Tap the Back arrow 
to return to the list of Rooms.
to return to the list of Rooms.Tap the Check Mark 
icon to exit Edit mode.
icon to exit Edit mode.