Blind testing a 1 db difference in volume: https://www.audiocheck.net/blindtests_level.php?lvl=1
I was surprised that when I repeated the test 10 times, I could identify the 1db change with 99.65% confidence. That was on the first pass, and with a little practice, I am certain that I could do it with 100% results. However, when testing audio devices, 1db is a large change!
There are smaller decibel differences in the testing that you can try. It is an interesting test site.