This is how you tell the THD+N audibility threshold for your stereo (spoiler: it’s quite high compared to amps here)

[evanf]

Take your preamp volume control level. I usually listen at -10db. I turned my system down at night and I could get -84db before pitch black silence. During the day? 10db or more worse. So. I need -60 to -65db SINAD for freedom from distortion. My Carver ALIII speakers have -60db for most of the band past 1kHz, that’s system wide distortion. Why should I get a -110db amp again???? I shoot for -80db in my electronics. A lot of the best sounding amps have THD around there.