I read the RX has sound generator, Is this the same concept as the NX? But NX has volume/on/off control under steering wheel. The NX sound, even at highest level is not too noticeable unless you know its on, then I can hear it.
I assume RX does not have the volume control? Its just always on?

Of course, both NX and RX are FSport.

 

It basically just diverts some of the air intake "suction" noise into the cabin. It is always on and of course varies with throttle position.

 

It is only in F-Sport

 

The NX sound is piped through the stereo speakers. In the RX it is through a baffle on the intake.