I agree and I know how my ear perform. Degradation comes mostly from the top end above 10kHz, which is not critical for music. Composing and directing music ar

I agree and I know how my ear perform. Degradation comes mostly from the top end above 10kHz, which is not critical for music. Composing and directing music are two very different activities. I'd expect the first one to work way better than the latter given strong deafness. I don't know about a successful deaf conductor in the modern times. Yet I think we are agreeing in the core - hearing music is more than just ears, it is also perception, which is why some people get wrong ideas about and if something sounds better (see the original topic here). Yet that does not mean there is not better gear than other and that no one can hear the difference between anything. Actually better hifi gear will sound better, even to older people.