Balanced melody, on the day (5)
I believe the answer is:
tuned
'balanced' is the definition.
Both the answer and definition are adjectives. Perhaps there's a link between them I don't understand?
'melody on the day' is the wordplay.
'melody' becomes 'tune' (synonyms).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'the day' becomes 'd' (abbreviation for day).
'tune'+'d'='TUNED'
Can you help me to learn more?
(Other definitions for tuned that I've seen before include "(Of note) adjusted" , "desired pitch" , "arranged for reception" , "Correctly pitched or adjusted" , "Adjusted frequency" .)