I don't know what 'WRT' stands for...
Anyway, you hear the slipstream noise on all aircraft. At first, the engine sound on takeoff is dominant, but as the speed increases to full cruising speed, the slipstream noise pretty much covers it up, unless you are in the rear, next to a fuselage mounted engine on an MD80, perhaps.
Some people like its "white noise" effect, as it also covers up other sounds like babies crying to some degree. Here is a sound recording of that sound, albeit, only at full speed...it doesn't show the difference from takeoff...
I find it difficult to hear the flight attendants, when they come around taking food and beverage orders. Normally, my hearing is very good, on the ground.
I actually like that "white noise" from the HVAC on Amfleet and Superliner's....for the same reason. Helps me sleep. It is only when it suddenly stops, that I awaken...