Patience produces clear tone (9)
I believe the answer is:
tolerance
'patience' is the definition.
(I've seen this before)
'produces clear tone' is the wordplay.
'produces' indicates anagramming the letters (I've seen 'producing' mean this).
'clear'+'tone'='cleartone'
'cleartone' is an anagram of 'TOLERANCE'.
(Other definitions for tolerance that I've seen before include "Ability to resist pain" , "resignation" , "Willingness to accept the behaviour of others" , "Being indulgent" , "example of permissiveness" .)