Cava, a modest correction: A 1-dB increase or decrease in SPL is the smallest (barely) detectable change in subjectively perceived loudness. A 3-dB increase is subjectively perceived by most listeners as "somewhat louder" (or "somewhat softer" if it's a 3-dB decrease in SPL).
Your other points I'd agree with.
Yeah, I guess my definition of "close" was not close enough...haha. Although when I listen to one of those cd's that repeats a tone in 1 dB decreasing increments I can't really tell that each step is quieter, just that it definitely gets quieter after several steps.
