[Goodallboy]

Originally Posted by Earl49

FWIW a change is sound pressure level of 3 dB is barely noticeable, and only under ideal conditions. Increases in loudness are generally judged as follows. Decreases in sound level follow the same scheme.

+ 1 dB -- measurable using a quality sound meter, but not perceptible
+ 3 dB -- noticeable if you are actively listening or expecting a change
+ 5 dB -- noticeable without prompting
+ 10 dB -- subjectively twice as loud as the original sound

The character of the tone might change - that is WAY harder to quantify -- but the loudness will not be perceptibly different.

All but the #1 entry is dependent on the listener so it is of little relevance across the population.