Fall back with louder song being played (4,6)
I believe the answer is:
lose ground
'fall back' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'with louder song being played' is the wordplay.
'with' says to put letters next to each other.
'being played' indicates an anagram.
'louder'+'song' is 'loudersong'.
'loudersong' with letters rearranged gives 'LOSE GROUND'.
Can you help me to learn more?
(Other definitions for lose ground that I've seen before include "fall behind?" , "Have nowhere for home matches" , "Fail to keep up" , "Give up advantage" .)