What are the unique sounds emitted by Embraer E190-E2 on final? I live close to an airport where these aircraft frequently land. When the E2 is between 2-3 thousand feet, something which I can only describe as whale moans, is heard.

I say they are unique because I can’t hear them from other aircraft. However, this airport seldom get heavy traffic, so maybe this sound is common among heavier aircraft—I wouldn’t know.
This was answered by an pilot acquaintance of mine:
The most recent generation of engines on the E2 comes with a geared turbofan. In the final stages of descent, the engines rotate at speeds which causes resonance in the combustion chamber. The distinct sound is that vibration.
This sound can also be heard when departing the gate, when the engine experiences similar rotational speeds.
Mitigation of this requires a redesign of the combustion chamber.