Band's new sound has tenor going low (5)
I believe the answer is:
nonet
'band's' is the definition.
(group of nine musicians)
'new sound has tenor going low' is the wordplay.
I cannot quite understand how this works, but
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is found within the answer.
'tenor' could be 't' and 't' is present in the answer.
'going' could be 'on' (both can mean functioning or activated) and 'on' is found within the answer.
A single letter 'e' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for nonet that I've seen before include "Musical composition -- tonne (anag)" , "Music for nine instruments or voices" , "baseball team" , "Composition for nine players" , "Piece for nine payers" .)