Some Dark Eldar Raiders have small modifications when they are ridden or operated by Haemonculi. These Raiders are known to contain a torture amp which allows a Haemonculus to torture captured slaves during the battle. The haemonculus's work traps the screams and voices of tortured slaves into special voice-boxes. These horrifying cries are filtered through complex projectors to create a wave of terrifying sonic energy around the vehicle. That special kind of sonic energy can scatter enemy units and make them flee in sheer horror of the voices.
- Codex: Dark Eldar (3rd Edition), pg. 13