の声は

one's voice

→ の
phrase Common #6,141
one's voice の marks possession, and は marks 声 as the topic. This phrase is normally followed by a description of the person's voice.
JA: 彼の声はとても優しい。
EN: His voice is very gentle.

騒音での声は届かなかった

The noise drowned out my voice.

の声は悪くない

Your voice isn't bad, but...

— コーラス (2004)

の声は聞こえてる

Can you hear me?

— 甘い生活 (1960)

子供の声はたやすく識別することが出来ます

Children's voices are easy to identify.

僕は窓のすぐ下にいて二人の声は聞こえた

I was right below the window and could hear the two of them talking.

— 落下の解剖学 (2023)

トニーの声は良い

Tony has a nice voice.

その少女の声はだんだん弱くなりました

The girl's voice gradually grew weaker.

部屋の後方の人には話し手の声は聞こえなかった

The people at the back of the room couldn't hear the speaker.

の声は不機嫌感じがする

You sound annoyed.

— ブエノスアイレス (1997)

の声はの声

The voice of the people is the voice of God.

— マレーナ (2000)

の声は聞こえてる

Can you hear the birds singing?

— 炎628 (1985)

の声は届いていますか

Can you hear me?

電話の声は私には聞き覚えのないものだった

The voice on the phone was unfamiliar to me.

の声はの声

The voice of the people is the voice of God.

子供の声はたやすく識別できる

Children's voices are easy to recognize.