Degree of loudness (6)
I believe the answer is:
volume
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">degree of loudness</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for volume that I've seen before include "Book; capacity" , "Publication" , "Magnitude of sound" , "Tome" , "Space occupied by an object" .)