Become quieter when confused aide finds route afterwards (3,4)
I believe the answer is:
die away
'become quieter' is the definition.
I can't judge whether this definition defines the answer.
'confused aide finds route afterwards' is the wordplay.
'confused' indicates anagramming the letters.
'finds' is a charade indicator (letters next to each other).
'route afterwards' becomes 'way' (way is a kind of route. I am not sure about the 'afterwards' bit.).
'aide' anagrammed gives 'diea'.
'diea'+'way'='DIE-AWAY'
'when' is the link.
Can you help me to learn more?
(Another definition for die away that I've seen is " slowly fade out".)