Praise be to Allah the Lord of the Worlds.
The woman`s voice isn`t Awrah, for the wives of the Prophet (PBUH) used to report narrations to the Prophet`s companions (May Allah be pleased with them) in addition to the rulings of Sharia. However, it is prohibited for a woman to be complaisant in her speech (thinning and amplifying). Allah the Almighty says, "O wives of the Prophet! You are not like any other women. If you fear [God], then do not be complaisant in your speech, lest he in whose heart is a sickness aspire [to you], but speak honourable words."{Al-Ahzaab, 33}.
Moreover, it is permissible for a woman to recite loudly in the presence of non-Mahram men if there is safety from temptation. Al-Bajirimi(May Allah have mercy on him) said, "It is prohibited that a man hears her voice, even when she is reciting Quran, if he feared getting tempted by it or enjoying it. Other than that, there is no prohibition."{Hashyat Al-Bajirimi, 3/372}.
The Hanbali jurist Ibn Mofleh(May Allah have mercy on him) says, "According to our more correct opinion, the voice of a non-Mahram woman isn`t Awrah, and it is prohibited for men to enjoy listening to it even in recitation.'{Al-Forou` Wa Tashih Al-Forou`, 8/190}.
In conclusion, it is permissible that a man listens to recitation of a non-Mahram woman. This provided that the recitation is conducted with a normal tone of voice without any thinning that would open the door for listeners to enjoy it or get aroused by it, and this varies from one woman to another. However, it is better for the Muslim woman to avoid reciting at the presence of non-Mahram men if there is no need for doing so. And Allah the Almighty knows best.