Non-concerted efforts
I believe the answer is:
solos
'non-concerted efforts' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for solos that I've seen before include "Numbers" , "Unaccompanied parts" , "Musical passages for one instrument" , "Pieces of music for one voice or instrument" , "Passages for one player" .)