Composition from Bliss on at auditorium (6)
I believe the answer is:
sonata
'composition' is the definition.
(thesaurus)
'from bliss on at auditorium' is the wordplay.
'from' indicates the answer is hidden within the clue.
'SONATA' is hidden within 'bliss on at auditorium'.
(Other definitions for sonata that I've seen before include "Instrumental composition for soloist" , "Sat on a kind of composition" , "Musical composition for a solo instrument" , "Musical composition for one instrument or two" , "musical performance" .)