Play-Fi allows you to configure two speakers into a stereo pair by selecting one to play Left channel audio, and the other to play Right channel audio. Play-Fi will then synchronize the audio into a single stereo stream, wirelessly.
To set this up, press the Play-Fi button to go to the speaker screen. Tap on the Options button to open up the menu in Android or open the context menu on iOS, and choose Stereo Setup.
You will then choose a Left speaker, and a Right speaker, and finally, you will give the paired speakers a new shared name, like “Den”. Once paired, the stereo pair will appear as a single speaker in the Play-Fi network, for all users and devices.