Year in orchestra -- great, on the whole (2,3,5)
I believe the answer is:
by and large
'on the whole' is the definition.
(both can mean 'generally')
'year in orchestra great' is the wordplay.
'year' becomes 'y'.
'in' is an insertion indicator.
'orchestra' becomes 'band' (large musical group).
'great' becomes 'large' (synonyms).
'y' inserted inside 'band' is 'byand'.
'byand'+'large'='BY AND LARGE'
(Other definitions for by and large that I've seen before include "for the most part" , "All things considered" , "On the whole" , "In general" , "In the main" .)