Adjust the volume - loud notes transposed all round (6)
I believe the answer is:
soften
'adjust the volume' is the definition.
'soften' can be an answer for 'adjust' (thesaurus). I am not certain of the 'the volume' bit.
'loud notes transposed all round' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'transposed' is an anagram indicator.
'all round' is an insertion indicator.
'notes' is an anagram of 'soten'.
'f' going within 'soten' is 'SOFTEN'.
Can you help me to learn more?
(Other definitions for soften that I've seen before include "Make more plastic" , "Mitigate" , "Mollify" , "Temper" , "Make less firm" .)