Our ambient composition for percussion instrument (10)
I believe the answer is:
tambourine
'for percussion instrument' is the definition.
(tambourine is a kind of percussion instrument)
'our ambient composition' is the wordplay.
'composition' indicates an anagram (letters arranged or composed in a different order).
'our'+'ambient'='ourambient'
'ourambient' is an anagram of 'TAMBOURINE'.
(Other definitions for tambourine that I've seen before include "drum" , "One uses jingles" , "Shaken instrument" , "Percussion instrument" .)