Hearing the voice of a woman during learning or Davening:
The singing voice of a woman is [Rabbinically] an Erva. This applies whether she is single or married, and even towards the voice of one’s own wife [even while she is pure]. [This applies to woman of all ages, whether old or young, and to women of all levels of attraction.] Being that the singing voice of a woman is an Erva, it is therefore [Rabbinically] forbidden for a man to recite Kerias Shema, or Daven, or recite words of Torah while hearing it. As stated above, this applies towards the singing voice of all women, whether single or married, and even one’s own wife. However, as stated above, the voice of her speech is not an Erva, even if she is married, and one may hence learn and Daven even while hearing her speaking voice.
If one can focus despite the singing: Even by the singing voice of a woman, if one is able to concentrate on his prayer to the point that he does not even consciously hear or pay attention to her voice, then it is permitted [to learn and Daven while hearing it]. [Thus, if one hears singing and is unable to stop them, he is to strengthen his concentration and ignore the singing in order so he is able to learn/Daven.]
If one recited Shema or Davened Shemoneh Esrei while hearing the singing of a woman, must he repeat the prayer?
Some Poskim rule he fulfills his obligation and is not required to repeat the prayer.
May a man Davening or learn if he can hear the recording of a woman singing?
Some Poskim rule it is permitted to hear a woman sing through a radio or recording if he does not know what she looks like. Other Poskim rule it is permitted even if he knows what she looks like. Other Poskim rule it is forbidden to hear her voice in all cases, even if he does not know what she looks like. Practically, so is the final ruling. Accordingly, one is not to Daven or learn when one can hear a woman sing even through a tape or radio unless he is able to remove his mind from the singing.
 Admur 75:6; Ketzos Hashulchan 9:7
 Admur ibid; Michaber ibid; Yireim 392; Rabbeinu Yona Brachos 25b
 Nishmas Adam 4:1; Kaf Hachaim 75:27; However see Michaber ibid; Perisha 21:2 on Tur E.H. 21 who rules that listening to the singing of an Erva is Biblcially forbidden.
 Admur 75:6; Michaber O.C. 75:3 and E.H. 21:1; Shmuel in Brachos 24a “The voice of a woman is an Erva”
The reason: This is learned from a verse in Shir Hashirim that states “Ki Kolecha Areiv:Because your voice is pleasant.” [Brachos ibid] From here we learn that the voice of a woman is attractive and contains a lust. [Rashi ibid]
 Admur ibid; M”A 75:6; Beis Shmuel E.H. 21:6 [regarding prayer]; Bear Sheva, brought in Beir Heiytiv 21:4 [regarding anytime]; Beis Oved 17; Chesed Lealafim 75:6; Ben Ish Chaiy Bo 13; Kaf Hachaim 75:21
Other opinions: Some Poskim rule that al
 Pashut; Piskeiy Teshuvos 75 footnote 106
 Admur ibid; Rama 75:3; Ohel Moed 5:5; Hagahos Maimanis
 Beis Oved; Ruach Chaim 75:2; Ben Ish Chaiy Bo 12-13; Kaf Hachaim 75:24
 Nishmas Adam 4:1; Kaf Hachaim 75:27
 Forbidden or only Lechatchila should avoid? Some Poskim rule it is forbidden from the letter of the law. [Darkei Moshe 75:3] Other Poskim rule that it is merely initially to be avoided. [Michaber ibid; Beis Yosef 75 “Proper to be careful”; P”M 75 A”A 6 writes the Rama in 75:3 rules like the Michaber, unlike his ruling in Darkei Moshe; Kaf Hachaim 75:25] Admur ibid rules like the Darkei Moshe that it is forbidden. The practical ramification is in a case of Bedeived, that one Davened while hearing her voice, and whether one must repeat the prayer. [P”M 75 A”A 6]
 Admur ibid in understanding of Rama ibid; M”A 75/6 in name of Lechem Chamudos Brachos 3/117; Beis Shmuel 21/4; Michaber 75/3 “Kol Zemer”; Rashba, brought in Beis Shmuel ibid; Yireim 392; Rabbeinu Yona Brachos 25b; This applies even to a married woman: Admur ibid; Machatzis Hashekel on M”A ibid; Chayeh Adam 4/6
 The reason: As since one is accustomed to hear her voice [and is therefore not stimulated by it] and it is therefore not an Erva. [Admur ibid; Rama ibid; Ravaya 76]
 Admur ibid; Olas Tamid 75:5; Rabbeinu Yona ibid; Kitzur SHU”A 5:16; Kaf Hachaim 75:26; See Beis Yosef 76
 Kitzur SHU”A ibid; Kaf Hachaim ibid
 P”M 75 A”A 6 based on Michaber 75:3 who rules one is merely to “beware” against Davening while hearing singing and does not write it is forbidden to do so; The Rama does not argue on this statement of the Michaber, even though he does in Darkei Moshe 75:3
 See Sichas Parshas Balak 7th Tamuz 1984 [Hisvadyus 1984 3/2124, printed in Shulchan Menachem 6/75]; Ohel Yaakov p. 205; Nitei Gavriel Yichud 54/11; Piskeiy Teshuvos 75:11 footnote 20
 Beis Shearim 33; One way of learning Maharam Shick E.H. 53
 The reason: As one is allowed to hear a woman’s voice if he does not know her identity, as the Yetzer Hara only has a lust towards that which he sees. [Beis Shearim 33; One way of learning Maharam Shick E.H. 53]
 Tzitz Eliezer 5/2; Yabia Omer 1/6; Rav Elyashiv, brought in Ohel Yaakov ibid
 The reason: As a radio sound and recording is not her real voice but a mechanical voice. [Poskim ibid]
 Peri Hasadeh 3/32; Ohel Moshe 1/32; Birchas Chaim 21; Birchas Shamayim 30; Poskim in Otzer Haposkim 21; Yaskil Avdi 5/12; Chelkas Yaakov 1/30 and 163; Minchas Yitzchak 7/70; Shevet Halevi 3/181; 5/197-3; Az Nidbaru 9/59; Rav SZ”A in Halichos Shlomo 20/12
 The reason: As one is not allowed to hear a woman’s voice even if he does not know her identity, as the rule that the Yetzer Hara only has a lust towards that which he sees was said only regarding future erotic thoughts, however at the time of the hearing of the sound, it certainly has erotic thoughts. Likewise, although the recorded sound is not the true voice, since it is similar and can bring to erotic thoughts there is therefore no reason to differentiate. [Poskim ibid]
 Nitei Gavriel Yichud 54/11 in name of Poskim ibid
 Rebbe ibid