According to the Quran, the sound of women’s voices in the presence of men is not forbidden
There is no rule in the Quran that women’s voices are forbidden in the presence of men. The rule that the voice of women is forbidden comes from the Jewish culture (Israiliyat).
The “do not speak too softly, lest the sick at heart lusts after you, but speak in an appropriate manner” (al-Ahzab 33:32) verse is used as proof that the voice of women is forbidden. However, the characteristic of this verse is not to forbid, but to use it as a measure that everyone accepts. If it were forbidden to talk to men, then it wouldn’t matter making an arrangement about it. The arrangement about using the voice is, according the taglib rule in Arabic, is valid for men too.
The other proof used about this topic, the “lower your voice” (Luqman 31:19) verse, is advice to men, not women! (The verse in an-Nur 24:31 has nothing to do with the voice, but to walk naturally).
The conclusion is that the voice of women is, according to the Quran, not forbidden. The purpose of the verse is advice to use the voice to protect women especially against men with bad intentions.