Evening event succeeded — tunes involved (6)
I believe the answer is:
sunset
'evening event' is the definition.
'succeeded tunes involved' is the wordplay.
'succeeded' becomes 's' (genealogical abbreviation).
'involved' indicates anagramming the letters (involved can mean confusing or complex).
'tunes' is an anagram of 'unset'.
's'+'unset'='SUNSET'
(Other definitions for sunset that I've seen before include "star not in the ascendant at this time" , "US nest (anag.)" , "Describes a declining industry or technology" , "End of the day in terms of light" , "'The dying of the 18'" .)