Unexpectedly vocal, energetic to begin with, in recess (6)
I believe the answer is:
alcove
'recess' is the definition.
(I know that alcove is a type of recess)
'unexpectedly vocal energetic to begin with' is the wordplay.
'unexpectedly' indicates an anagram.
'to begin with' says to take the initial letters.
The first letter of 'energetic' is 'e'.
'vocal' is an anagram of 'alcov'.
'alcov'+'e'='ALCOVE'
'in' acts as a link.
(Other definitions for alcove that I've seen before include "Recessed area" , "corner" , "Small recess in a larger room" , "bay" , "Niche - retreat" .)