Scottish group on key makes ringing sound (5)
I believe the answer is:
clang
'ringing sound' is the definition.
(I've seen this before)
'scottish group on key' is the wordplay.
'scottish group' becomes 'clan' (family or group of families in Scotland).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'key' becomes 'g' (musical key).
'clan'+'g'='CLANG'
'makes' is the link.
(Other definitions for clang that I've seen before include "Noise as of cymbals" , "Harsh cry" , "Ring of metal" , "Resounding effect" , "Jangle" .)