When a piece of music changes dynamics to a really low volume. Common in jazz music, classical, and rock.
"In The Mood" performed by Glenn Miller's ensemble portrays an uber-softee very well when the band repeats a 12 bar blues over and over, lowering the volume each time. They eventually make it so low that it become an "uber-softee
Measure 72 has a decrescendo. We're going to take it down to an uber-softee