He defied everyone else's request not to play his music so loud.
He played his music really loud which was a disturbance to everyone else, but he didn't care at all.
ーHe defied everyone else's request not to play his music so loud.
「彼は音楽を大音量で流さないで欲しいというみんなの要求を無視した」
to defy で「無視する・反抗する」
to play one's music so loud で「音楽を大音量で流す」
defy を使って日本語に近いように訳すとこのように言えますが、ちょっとかたい言い方です。
ーHe played his music really loud which was a disturbance to everyone else, but he didn't care at all.
「彼は音楽を大音量で流し、みんなの迷惑だったが、全く気にしなかった」
disturbance で「騒ぎ・邪魔」
didn't care at all で「全く気にしなかった」
ご参考まで！
カナダ 
