If you are playing from Bluetooth, you can wirelessly link 2 GSP Series speakers using TWS.
Pair your Bluetooth device with the first speaker; this will become the "Master" speaker. Press the MODE button to enter Bluetooth mode. The display will read BLUE, and the Bluetooth logo will flash to show pairing mode. On your Bluetooth device, select "GEMINI GSP Series." You can now play music to the Master speaker. Now power on the second speaker if not on already; this will become the "Link" speaker. Press the BT LINK button on both speakers, and pairing will happen automatically. You should hear stereo audio from the two speakers (Master Speaker = Left / Link Speaker = Right.) Use each speaker's volume knob to adjust to the desired level.
PLEASE NOTE: If you are playing any audio source other than Bluetooth, TWS Linking is not available. But it is possible to connect two (or more) speakers together by "Daisy-chaining." This will pass the master audio from one speaker to the next. Connect an XLR cable from the MIX OUT of one GSP Series speaker to LINE INPUT on the subsequent speaker. Use each speaker's volume knob to adjust to the preferred level.