Yes, a Sonos amplifier can be set to a mono operation. In mono mode, the Sonos amplifier will send a mono signal to all speakers. There are a couple of situations where mono mode may be desirable. Indoors, you may want to use the mono mode when, for budget purposes, you may only want 1 speaker in certain rooms such as a Dining Room/Living Room combination, or a Master Bedroom/Master Bath combination. It is important to remember in these situations, both rooms would be on at the same time, playing the same source, at the same volume. There would be no individual control or stereo separation in these combined rooms. This is not an ideal situation. For outdoor zones, mono mode is a good solution when you are trying to cover a large area and stereo separation is not important. Normally outdoors, you would be playing the same source at the same volume and individual control is not critical. With the Sonos amplifier, you could install up to 4 outdoor speakers on a single Sonos amplifier and cover a large area. For help in designing your Home Entertainment system, schedule your FREE consultation by calling 888-775-2673. Please visit our website @ www.wbsouth.com.