Very revolutionary beat associated with a piece of music (6)
I believe the answer is:
sonata
'piece of music' is the definition.
(type of musical composition)
'very revolutionary beat associated with a' is the wordplay.
'very' becomes 'so' (both can mean 'extremely').
'revolutionary beat' becomes 'nat' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'associated with' says to put letters next to each other.
'so'+'nat'+'a'='SONATA'
(Other definitions for sonata that I've seen before include "musical performance" , "Musical composition for one instrument or two" , "See 6" , "Solo piano composition" , "Music to play (not sing)" .)