Usage patterns
〈事〉が明瞭だfor something (speech, sound, meaning) to be clear/distinct
His pronunciation is extremely clear.
明瞭に〈動詞〉to do something (speak, state, etc.) clearly
He stated his opinion clearly.
〈事〉を明瞭にするto make something clear
It's necessary to make the purpose of the meeting clear.
明瞭な〈物〉a clear, distinct (explanation, image, etc.)
The teacher gave a clear explanation.