What are the unique sounds emitted by Embraer E190-E2 on final?
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.