The most common and most likely answer to this crossword clue is the 9 letter word MEGAPHONE
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result MEGAPHONE
Buddy explains!
The straight part
We know that "that usually raises voice" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that usually raises voice = megaphone.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MEGAPHONE mean?
MEGAPHONE noun- A portable, usually hand-held, funnel-shaped device that is used to amplify a person’s natural voice toward a targeted direction.
- Mouthpiece or promoter; one who speaks for or publicizes on behalf of another.
- To use a megaphone; to speak through a megaphone.
- A cytotoxic neolignan obtained from the laurel Aniba megaphylla.