Listening to Women Sing
Kol Isha Overview
- A woman’s voice is considered Ervah (nakedness) of a woman and it is absolutely forbidden for a man to listen to a woman's voice.  There's a major dispute whether this severe prohibition is biblical or rabbinic, however, everyone agrees that arousing improper thoughts is a biblical prohibition.  Therefore, one is not allowed to listen to a woman singing. 
- This prohibition applies at all times and not just when one is reading Shema. 
Who is Included?
- One may not listen to a married woman sing.
- One may listen to his own wife but not while he is praying or saying a beracha.
- Some poskim are lenient to allow one to listen to his wife even while she is a Nidda. Others are strict.
- One may not listen to a non Jewish girl sing under any circumstance, even if they are below the age of eleven.
- Some authorities are lenient when two women sing together because two voices can’t be heard simultaneously.  However, most poskim seem to disagree. 
- Some are lenient to allow listening to a woman's voice on a tape or radio if one doesn't know what the singer looks like (but prohibit listening to a woman's voice when one does know what the singer looks like, even if one doesn't see her when one is listening), and some are even lenient when one does know what she looks like.  Of course, this is only when the song isn't a sexual or inappropriate song. 
- One may listen to a woman's non-singing voice. 
- There is a discussion in the poskim if it is permissible to listen to a woman speak in public. 
- Gemara Berachot 24a based on Shir Hashirim (2:14) כי קולך ערב ומראיך נאוה, Shulchan Aruch E”H 75:3, Mishna Brurah 75:17. Sh”t Yabia Omer 1:6. see also Aish.com
- Gemara Avoda Zara 20b learns from the Pasuk “VeNishmarta MeKol Dvar Raah” that that a person may not have arousing thoughts. Tosfot s.v. Shelo understands this is a biblical prohibition as it’s based on a pasuk. Rabbenu Yonah (Igeret HaTeshuva 19-20, quoted by Bet Yosef E”H 21:1) agrees and adds that even arousing thoughts about a single woman are a Biblical prohibition. Bet Shmuel 21:2 writes that everyone agrees that an arousing thought is a Biblical prohibition (however, see Sh”t Achiezer 3:25(5) who writes that the Rambam holds having arousing thoughts is only a Rabbinic prohibition).
- Sh”t Yabia Omer 1:6(8) writes that since having an arousing thoughts is Deoritta then listening to a woman’s voice which may cause one to have arousing thoughts is a Safek Deoritta which is a general dispute whether Safek Deoritta is a Issur Deoritta or Issur Derabbanan (Rambam Tumat Met 9:12 holds it’s Derabbanan and Rashba Kiddushin 73a holds it’s Deoritta).
- Sh”t Yabia Omer 1:6(9) quotes the Bet Shmuel 24:2 and Maggid Mishna (Issurei Biyah 21:2) who understand that the Rambam holds that looking at a woman’s bueaty is Derabbanan prohibition, however, he argues based on the Rambam Pirush Mishnayot (Sanhedrin 54) and Sefer Mitzvot (Lo Taaseh 353) that this is an Isser Deoritta.
- In conclusion, there’s a major dispute whether this is a biblical or rabbinic prohibition. Sh”t Yabia Omer 1:6(10) writes that it may be considered a rabbinic prohibition when taking into account other considerations. Mishna Brurah 75:17 quotes the Chaye Adam (same author as Nishmat Adam) and seems to agree with those who say it's a rabbinic prohibition.
- Shulchan Aruch O"C 75:3, E"H 21:1
- S”A E”H 21:2
- Magen Avraham OC 75:6
- Rama OC 75:3
- Chemdas Moshe 58, Sh"t Yabia Omer YD 4:15, Taharat Habayit v. 2 p. 167, Taharat Yosef 3:40, Umekarev Biyamin vol. 1 pg. 163, Rabbi Mordechai Willig (Niddah Shiur 126 (min. 46-8)). Mishmeret Hatahara 195 fnt. 207 quotes Rav Elyashiv as being lenient according to the strict halacha unless she is singing for him.
- Pitchei Teshuva YD 195:10, Iggerot Moshe YD 2:75, Aruch Hashulchan OC 75:23, Kitzur Shulchan Aruch 153:10, Avnei Yashfei OC 2:5,
- Iggerot Moshe OC 4:15:2
- Sh”t Sridei Esh 2:8 quoting Rav Azriel Hildesheimer and Rav Shimshon Raphael Hirsch. Chatan Sofer (Taharat Yadayim 14) agrees.
- Beer Sheva (Beer Mayim Chaim 3), the Steipler (cited in Journal Ohel Moshe 1992), Sh"t Shevet Halevi 4:197, Badei Hashulchan Nidah 199:119, Kinyan Torah 85, Avnei Yashfei 2:5, Ishei Yisrael 55:32, and Nitei Gavriel Yichud pg. 348
- Yalkut Yosef (Otzer Dinim LeIsha pg 386), Halichot Olam (vol 1, pg 124).
- Sh”t Yabia Omer 1:4(1) writes that perhaps if one doesn’t see the woman singing it’s not an issue based on the Gemara Sanhedrin 45 which says that a man’s thoughts are only aroused when seeing a woman. He continues that even if one doesn’t see her but one recognizes her it’s certainly forbidden based on the Gemara Megillah 15 which says that men would have improper thoughts by simply saying Rachav’s name because they once recognized her. He supports this point by quoting Gemara Avoda Zara 20b which says that one may not look at the nice clothing of a woman even when she’s not wearing them because they may arouse thoughts and that’s only when one recognizes her. See Sh”t Maharam Shik E”H 53 who is also lenient if one doesn’t know what the women looks like, whereas the Sh”t Chelkat Yacov 1:163 is strict.
- Sh”t Yabia Omer 1:6(13) concludes that if one recognizes a woman even by having seen her picture it’s forbidden to listen to her voice on a tape or radio, however, if one doesn’t recognize her it’s permitted to listen to her voice on a tape or radio. See Sh”t Tzitz Eliezer 5:2 and Sh”t Maharshag 2:118 are lenient with regards to the radio, whereas the Sh"t Mishna Halachot 4:86 is strict about this.
- see also Rabbi Aryeh Lebowitz Ten Minute Halacha on Kol Isha on Recorded Music
- Yalkut Yosef (Tefilah Pesukei DeZimra pg 673)
- Bet Shmuel E"H 21:4 writes that one may listen to a woman's non-singing voice. Mishna Brurah 75:18 writes that one may not have intent to get benefit from a woman's voice even if one is regular to hear that voice. Chacham Ovadia Yosef in Yabia Omer (O"C 1:6:11) extends the prohibition even in cases where one is used to hearing a woman's voice.
- Sh"t Shevet halevi 3:14 forbids it, arguing that the a speaking voice should be permitted, a public speaking voice is very different and potentially more stimulating.
- Sh"t Iggerot Moshe OC 5:13 is lenient as those as it isn't giving in a shul and the woman is sitting.
- Lehorot Natan 1:60 also permitted a women to speak in front of men as the prohibition of kol isha is only if a mans enjoys the sound of her voice but not if he is focused on the content.