Alto or soprano (5)
I believe the answer is:
voice
This clue is a double definition.
'alto' is the first definition.
(thesaurus)
'soprano' is the second definition.
(thesaurus)
(Other definitions for voice that I've seen before include "Wallop" , "Utter - part" , "Express, utter" , "Articulate" , "Sound of speaker" .)