The Speaker B connections on the back of the amplifier allow for a second set of speakers to be used (i.e. speakers located in another room).
The Speaker A/B button on the front panel and remote control allows the two sets of speakers to be toggled on and off.
Either A or B, or both A and B may be selected for use.
Note: When using two pairs of speakers, use speakers with a nominal impedance of 8 ohms each.