More than one channel editor captivated by vaulting ambition (5)
I believe the answer is:
media
'more than one channel' is the definition.
'editor captivated by vaulting ambition' is the wordplay.
'editor' becomes 'ed'.
'captivated by' indicates putting letters inside.
'vaulting' says the letters should be written backwards.
'ambition' becomes 'aim' (I've seen this before).
'aim' in reverse letter order is 'mia'.
'ed' inserted inside 'mia' is 'MEDIA'.
(Other definitions for media that I've seen before include "News channels" , "Mass communicators" , "News industry" , "Eg, newspapers, TV" , "The 14, for example" .)