Thank you for your help. It does look pretty much like a hardware issue indeed. 😟
Well, my unit is production week 43, rbrylawski's unit is a week older. Obviously, production week is no indicator - welcome to the exchange lottery.
@David:
According to iFixit's teardown pictures there's not much located in the top left corner. There's the headphone jack, an ambient light sensor, a WiFi antenna and a piece of the battery.
@psikofunkster:
The speakers itself aren't to blame, they just pop coz they get a spike of current from the circuit to which they are connected. That's the part to blame, imho.
Seems psikofunkster, the other people and I bought a ticket for the Titanic.
Merry Christmas to all!