I am fascinated by people who can hear any of these properties. My wife will tell me "so and so (millions of records sold) always sings off key" and I'm left to

I am fascinated by people who can hear any of these properties. My wife will tell me "so and so (millions of records sold) always sings off key" and I'm left to wonder what it would be like if I could hear that. Never mind hearing good relative pitch (e.g. the frequencies are all relatively correct but the notes are A432 or A444 rather than A440). Someone once tried to teach me about I-V-VII in rock music and I think I can hear it but I don't know what I'm hearing really. I think I can hear discordance and I think I can tell when blue notes are used. My reference for 400 Hz is the high-pitched "hum" you used to hear in airline audio headsets. But these are just memories and not analytical tools. Congratulations to all of you who can sing in a choir without pissing off your choir-mates.