"There are three main inputs selectable from a switch on the front, as well as a separate input for each set of channels if you desire to have different sources playing in different zones. This option is selectable using a toggle switch beside each volume control for each set of channels."

You can buy with 2, 4, 6 or 8 channels.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated