Soothing LED cut out (6)
I believe the answer is:
dulcet
'soothing' is the definition.
('dulcet' can be a synonym of 'soothing')
'led cut out' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'led'+'cut'='ledcut'
'ledcut' with letters rearranged gives 'DULCET'.
(Other definitions for dulcet that I've seen before include "Soft and pleasant sounding" , "Harmonious, melodious" , "(Of sound) melodious" , "Mellifluous, pleasant to the ear" , "(Of sound) sweet and soothing" .)