When run in stereo mode, I can't hear the violins at one end of my yard. Why?
Stereo doesn't work well outdoors, unless you place the rocks fairly close together, as when used on a small patio or around a hot tub. For larger, open areas, we recommend you run the rocks in "mono" mode, so all the frequencies are sent to each speaker.
Unlike with indoor speaker use, outdoors there are no walls or ceilings to contain the sound, which dissipates quite quickly. Running in mono mode ensures that you'll hear the violins no matter where in the yard you are listening.