noun
very loud voice
Refers to an extremely loud voice, often used in contexts like shouting, cheering, or making a powerful vocal declaration.
彼は大音声で叫んだ。
He shouted in a very loud voice.
大声 is the common word for 'loud voice'; 大音声 is more emphatic and less frequently used.
Compound of 大 (dai, 'big') and 音声 (onjō, 'voice' or 'sound'). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning of a very loud voice.