Instrument with a bell (4)
I believe the answer is:
oboe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">instrument with a bell</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for oboe that I've seen before include "it's blown" , "source of notes" , "Instrument used in 1d" , "Source of music" , "Producer of notes" .)