WRX series: How to connect a line-level source to your WRX speaker
A line-level source is any device that puts out a full-strength audio signal, not a microphone-level signal. On your Gemini Sound WRX series speaker, how you connect it depends on whether the source is stereo or mono.
Stereo devices (DJ mixer, drum machine, AUX cable, etc.)
If your stereo device has an RCA or 1/8" output, connect it to the matching input jack on Ch 3/4.

If your stereo device has 2 x XLR outputs, connect them to Channels 1 and 2 with the LINE/MIC switch depressed for LINE mode.

Once the stereo device is connected, set the Master Volume to your preferred level. Use the LEVEL knob to adjust the volume while speaking into the microphone until it sounds right.

Mono instruments (keyboard, active guitar/bass, etc.)
Connect to the inner 1/4" jack of channel 1 or 2 with the LINE/MIC switch depressed for LINE mode.
Once the mono source is connected, set the Master Volume to your preferred level, then use the LEVEL knob to adjust the volume while playing the instrument until it sounds right.