I've had the Dyson Pure Hot + Cool Link for about 6 yrs now and have been putting up with a low to medium pitch motor whine at fan speeds slower than level 3. While it is tolerable in a large siiting room or during the day when I'm awake, it is annoying during the night when used in the bedroom and the fan drops to the low speeds in Auto which causes interrupted sleep.
Please listen to these audio recordings on my Google drive and advise if this is normal. There is no difference between Hot or Cool modes.
1. Unit off on continuous monitoring https://drive.google.com/file/d/1gaAncyYmk74QGD21M4b1TlDOiON1F8nB/view?usp=drivesdk
2. Unit on at fan level 1 https://drive.google.com/file/d/1gkltKqyZ6t048zJIDtIGTA6NZ-xKRSsf/view?usp=drivesdk
3. Unit on at fan level 2 https://drive.google.com/file/d/1gq6YF7FIMbnPE6RPdOVB0Ui6vusT3iII/view?usp=drivesdk