Hi all, 
a very happy, safe and healthy New Year to everybody here (and their families). 
I have a question about my external HDD and wonder if anybody can tell me more about a certain “noise”.
To begin with I have to say I´m using the external HDD “WD Elements 25A2” as may main drive, i.e. my system Lubuntu 20.04 is installed here.
The HDD is connected via USB 2.0 to a hub which itself is powered by a power supply of its own.
That scenario has been working well ever since I put it up.
Over night (after shutting down my PC) I also switch off the power supply of the hub and the next day (before pressing the power button of the PC in order to get started again) I switch on the power supply of the hub.
A second or two after the HDD gets power I notice a very short “whizzing” sound. It´s a bit hard to describe; a high-pitchend sound anyway (but not a “click”).
But (as I said) it´s very short, more like a “pling”, definitively less than a second of duration.
I guess this sound is produced as the the spinning part of the HDD reaches its maximum speed of rotation 
…
For the whole duration of the session (hours on end) this sound can never be heard again, just at the beginning when the HDD spins up.
Plus: the sound is barely audible; in fact I´ve noticed it the other day by sheer coincidence (I was remaining very still for a while).
Otherwise I wouldn´t have noticed it at all. 
So it may very well be that the sound has been there from the beginning of the usage of the HDD (some years now).
I´d very much like to hear what you think about it.
May it be that this kind of behaviour of a HDD is normal
Thanks so much in advance.
Many greetings from Rosika 