IPA: /ʌnˈmʌfəld/
KK: /ʌnˈmʌfəld/
Not covered or softened, allowing sound to be heard clearly.
The unmuffled sound of the train could be heard from miles away.
Unmuffled → It is formed from "un-" (meaning not) and "muffle" (from Middle English *mufflen*, meaning to wrap up or cover). The word "unmuffled" means not wrapped up or covered, allowing sound to be clear and unobstructed.
Think of 'not' ('un-') covering or wrapping something ('muffle') — that's why unmuffled means sound that is clear and not covered.