Youngsters need a smaller music centre (6)
I believe the answer is:
minors
'youngsters' is the definition.
('minor' can be a synonym of 'youngster')
'smaller music centre' is the wordplay.
'smaller' becomes 'minor' (I've seen this before).
'centre' says to take the centre.
The middle letter of 'music' is 's'.
'minor'+'s'='MINORS'
'need a' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for minors that I've seen before include "They're too young to vote" , "They are legally under-age" , "Young people" , "could be little ones" , "They're under-age" .)