When using 2 speakers with ECOCONNECT, here is what we've found to be most successful.
Ecoboulder-
Turn one speaker on, connect to bluetooth and press the ECOCONNECT (double diamond) button-don't press and hold, just press and release. You should hear a beep.
Turn the 2nd speaker on (whether Ecoboulder or EcoSlate) and press the ECOCONNECT (double diamond) button until you hear the beep, you will hear "connection successful".
EcoSlate/EcoDrift
Turn one speaker on-before connecting to bluetooth, press the ECOCONNECT button -press and release...DON'T press and hold...you will hear a beep.
Turn the second speaker on and press the ECOCONNECT Button, you will hear the beep, then "connection successful"
Then connect to your bluetooth.