Unnaturally high voice (8)
I believe the answer is:
falsetto
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unnaturally high voice</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for falsetto that I've seen before include "Abnormally high voice" , "Artificially high singing voice" , "Artificial pitch" , "High vocal range" , "Unnaturally high voice" .)