JBL EON One Pro - Connecting 2 together with pass-thru
I have recently purchased a second JBL EON One Pro PA and I was advised by the supplier that all I needed to do was to use an XLR cable plugged into the pass-thru output into one of the channel inputs in the second PA. When I do this, I get absolutely no volume from the second PA. The only way I can get any sound out of the second PA is to have the channel volume up to maximum and the master volume also at max. The other issue that I have is when I plug in my NORD Piano4 and have the input channel set to line, I also get very low volume with the piano plugged into this channel. When I press on the mic/Line button and it changes to MIC, the volume level is high. It is extremely frustrating that I have spent nearly $4000AUD on these PA's and I am not getting the level of performance that I expect.
This is not to be confused with the app ability to link 2 speakers together via Bluetooth - that connection is strictly for streaming audio from another device such as an Ipad or phone and will not work in live performance situations - for guitar/mic you need to connect the speakers manually with a cord/cable.
As far as your piano make sure the piano is outputting a line level signal..if not then there will be an impedance mismatch resulting in low volume. If going through the xlr input set to mic works simply set your piano to a medium volume and slowly adjust the gain on the JBL until you reach your desired level and it should work fine. I use my Roland that way on occasion. Remember, never use inout one due to its phantom power capability as you could damage your keyboard.