Biamp Commercial Audio ZONE4 Built-in display4 Zone, 20 30000 Hz, SNR >90 dB, 483 x 205 x 44 mm, 2. 75 kg The sophisticated pre amplifier ZONE4 allows you to control four stereo zones with just one affordable unit. In any of the 4 zones you can play music that comes from one of the 4 music sources you can connect. There is also the possibility to assign 3 microphones to each zone where MIC1 can be a dynamic priority mic (via contact closure) or a 4 zone selective paging microphone (MICPAT 4).