The MXW70 includes a switchable 'Mono Mode' feature which allows you to use one power amplifier to amplify the left channel of your stereo setup, and another to power the right channel. This can be used with both balanced, and unbalanced connections to the amplifiers.
With Mono Mode enabled each amplifier will provide 250W at 8 Ohms only - it is not possible to use a lower impedance speaker in this configuration. Once enabled, speaker connections are made using the two red terminals on the rear panel of the MXW70, and the polarity for each is indicated below the speaker output section.