No audio from Rackmode Vocoder

In order to hear anything from the Rackmode Vocoder or Rackmode Vocoder FX, you'll need to use your DAW's sidechaining feature to route audio from another track into the vocoder. A typical example would be to use Rackmode Vocoder on a MIDI track, and then set the sidechain to receive vocals from an audio track.

Video:

Setting Up The Rackmode Signal Processors Vocoder