httpv://www.youtube.com/watch?v=D9cLAFzexBo&feature=player_embedded
TSS or Turbine Sound Studios, have recorded with high fidelity audio equipments the RB-211 engines sounds mounted on the Lockheed Martin L-1011 TriStar.
Purchase either the FSX or FS2004 package so you can hear now the highly realistic soundset in your speakers or headset.