RVox uses “downward compression” on peaks and “upward compression” on soft parts simultaneously. No other plugin does it exactly this way.
If you are looking for that specific "RVox sound" without the cost, consider these options:
How to do it: Go to the official Waves website → Search "Renaissance Vox" → Click "Try Demo."
To emulate RVox with free plugins, insert a gate (like ReaGate in Reaper or Cockos’ free plugins) followed by a smooth compressor with auto-release. Set the threshold low to catch whispers.