Note:
The B206 main rotor beat frequency is quite low (13Hz and lower) which may cause rattling on some setups. In general if something is rattling or knocking about, turn overall volume down. If resulting effects are insufficient, turn overall volume back up to point of rattling and turn each effect on by itself one at a time to determine which effect is causing the rattling, then turn THAT effect down before turning all the effects back on.