Ralph Mowery brought next idea :
In article , lid
says...

Per TNSTAAFL:
We're looking at two Bosch dishwashers - one claims a noise level of 50 db,
and the other a noise level of 53 db - the features and functionality are
pretty much the same - there's about a $100 price difference.

I can't speak to db except to note that the db scale is logarithmic -
i.e. 50 vs 51 is a lot bigger than it sounds.


One Db is not vety much in sound level. To the ear it should be just
the minimum change that you can detect with average hearing. To get a
an idea about db, for 3 db of change double the distance. Say listen to
something at 2 feet away and then back up 2 more feet. At 8 feet it
would be 6 db of difference and to get to 10 db you have to back up to
20 feet.

Double the distance and the sound level should fall 6db as it falls off
by the 'square' of the distance.