Locate the Input Configuration switch on the back of the amplifier and switch it to the "Bridge" position. The switch offers three configuration choices: Bridge, Stereo and Parallel. The Bridge position is at the top of the three choices.
Plug the speakers into the CH1 (channel one) Speakon speaker output. If the binding posts are used instead of the Speakon connector, connect the positive speaker wire to the CH1's positive (+) post and the negative speaker wire to the CH2's negative (-) post. The diagram on the back of the amp will assist you in locating the posts.
Plug the mixer output into the QSC amplifier CH1 input, using a low impedance cable. Either three-pin XLR or stereo 1/4-inch connectors may be used for the amplifier input. XLR connectors use standard wiring (pin 1= ground, pin 2 = positive, pin 3 = negative). Stereo 1/4-inch TRS (tip/ring/sleeve) connectors use standard positive tip, negative ring, grounded sleeve wiring. If using unbalanced cables, which should only be used for very short input cable runs, XLR pins 1 and 3, or TRS tip and ring should be internally jumped.
Turn the amplifier and mixer volumes to minimum, then turn on power switches to both units.
Turn the QSC CH1 and mixer volume up to required levels, and perform a sound check. The QSC PLX amplifier's CH2 volume is disabled in bridge mode and should be kept all the way down.