By adding Oradea's expander Arad, you gain three additional features. Arad features direct audio inputs for individual channels, so you can use each channel for a different audio source (the individual channel outputs are already incorporated into the main module). There are buttons and gate inputs for manual and/or remote clickless muting and unmuting of the channels. Another group of four buttons acts in parallel to the TRIG inputs of Oradea, allowing for manual triggering.