その音で

at the sound of that

→ 其の
phrase Rare #36,710
at the sound of that で indicates that the sound is the cause or trigger of an action or reaction, such as waking up, flying away, or becoming excited.
JA: その音で犬が目を覚ました。
EN: The dog woke up at the sound of that.

その音で目覚めた

I woke up to that sound.

その音で鳥は飛び去った

The bird flew away at the sound.

私たちはその音で興奮した

We got excited by that sound.

その音で私は目覚めた

That sound woke me up.