They synchronise musicians put on in clubs (6)
I believe the answer is:
batons
'they synchronise musicians' is the definition.
The definition suggests an adverb but the answer is not.
'on in clubs' is the wordplay.
'in' indicates putting letters inside.
'clubs' becomes 'bats' (bat is a kind of club).
'on' placed inside 'bats' is 'BATONS'.
'put' is the link.
Can you help me to learn more?
(Other definitions for batons that I've seen before include "Rods for conductors and coppers" , "Rods for conductors and police" , "Conductors flourish them, or policemen" , "With which to conduct" , "Conductors wield them - or policemen" .)