Holy person, before getting halo, must be kind of sound (6)
I believe the answer is:
stereo
'kind of sound' is the definition.
(I've seen this in another clue)
'holy person before getting halo' is the wordplay.
'holy person' becomes 'st' (short for saint).
'before' becomes 'ere' (poetic term for 'before').
'getting' means one lot of letters go next to another.
'halo' becomes 'o' (O resembles a halo).
'st'+'ere'+'o'='STEREO'
'must be' is the link.
(Other definitions for stereo that I've seen before include "Sound coming from different directions" , "Tape recorder" , "Music player with two speakers" , "Two-channel sound" , "Record player" .)