Flute, lovely rhythm (6)
I believe the answer is:
groove
I believe this is a double definition.
'flute' is the first definition.
(thesaurus)
'lovely rhythm' is the second definition.
(groove can mean a musical rhythm)
(Other definitions for groove that I've seen before include "Established routine" , "Long shallow depression or routine" , "Long thin furrow" , "Gramophone record track" , "Long narrow depression - dance and/or play popular music" .)