Loud and clear (7)
I believe the answer is:
clarion
'loud and clear' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for clarion that I've seen before include "Loud and clear; shrill war trumpet" , "In church maybe stop" , "A loud rousing sound" , "It makes a shrill note" , "Medieval brass instrument with a clear shrill tone" .)