On the Aeromax, the noise doesn't stop when the intensity of the fan speed is increased, you simply can't hear the noise over the fan at full blast. As above, the sound derives from a piece of code in the CAN bus system onboard the Aeromax, which causes the fan to resonate.
At one point MMC thought the CAN could not be reprogrammed in an attempt to better/remove the code that caused the noise; however, they have recently (as in the last 4-weeks) found a solution. I am not sure if the software has to be updated, or whether the fan unit is replaced by one with code already installed - I will ask and report back. All I can tell you is that the noise is no longer present in my Aeromax because MMC fixed it.
Reference the other issue - I have never heard the sound mentioned but said to EL77, he was welcome to have a listen to my car (as a comparison).
