Can I use multiple AIR companion speakers in one set up?

Yes, absolutely. Any 8000X, 8000XU1, or 8000XU2 can transmit to an unlimited number of AIR wireless companion speakers. All units should be set to the same frequency to receive signal. When setting up your arrangement, be sure to point the systems facing the same direction – pointing the systems directly at one another may cause distortion. AIR units can be placed 300+ feet (or more in ideal conditions) from the transmitting main unit.