I’ve already noticed after flying 8 years on the 320 I can no longer hear the radio even when the loudspeaker is cranked up to max. So now I keep the speaker turned off in flight, and left ear piece in the whole time so that I can hear ATC. I give FOs a choice on whether to wear their headset above 180 or not. I don’t care if the FO wants to wear the headset or not. But FOs that bring their own headset tend to keep them on and the ones that don’t take them off. If they take theirs off, I take my right ear piece off and sometimes I hear them if they yell loud enough…

The 319s are the worst and the loudest plane.
NEOs with the inop propsync give me headaches, but noise canceling make all the engine, prop noises and airflow noises go away on the 320s and 321. The 319s you still hear the engines with active noise cancelling.