Isn't decibels dictated by speaker sensitivity?
Yes, the dB level reaching your ears is partially down to speaker sensitivity - so for that reason you can't expect your LED ring to display the actual level you listen at.
(Regardless of how it's response to adjustment is calibrated, or how the LEDs are marked).
But it
might be giving a very accurate indication of relative level changes.
I say 'might' because the calibration and resolution is critical.
Take my example:
Old Cyrus amp had a ring of 15 LEDs around the volume knob.
New Cyrus amp electronically displays 1dB increments from a -80dB min, to the 0dB max.
So the old amp's LEDs had nowhere near enough resolution - plus the fact that the range was not calibrated evenly across them (wasn't a linear response).
Would be interesting to know what your Leema LEDs represent.....if there were enough of them, they could be showing 1dB changes??
(1dB is recognised by many as being about the lowest change audibly detectable - though others claim to be able to hear lower figures.....probably the same ones that hear the magic of cables).