Hotdog,
Unless I missunderstood what you said..........Fan Speed makes all the difference when it comes to engine noise. In fact, lowering RPM by 10 will change the noise output of an aircraft by a few tenths of a dB. Not that the noise source has changed, the increase in noise is mostly due to being lower over the mic.
Example: Adding the N1 monitor to CF650 engines lowered climb out RPM by about 9 RPM this was a 0.2 EPNdB change.
I could spend a few hours taking those that care through Noise 101, but I don't think anybody would really care.
As an FYI - the GE powered 777s are certified quieter than the Trents. The growl you hear is what is called "Buzzsaw" noise and will be fixed by a new inlet that will be available come July this year. I don't understand the whistle noise you are claiming to hear. It could be turbo machinery noise that is louder than the engines, but if that is true the noise certification of those aircraft is bogus.
