Office of Grand Ayatollah Khamenei (may Allah grant him long life):
1. If the singing is ruled as ghinā, it is ḥarām and the content makes no difference.  Similarly, if one listens to her voice with the intention of seeking pleasure or if it entails evil or it is accompanied with licentious and forbidden music, it is not permissible.
2. Ghinā is a kind of singing accompanied by vocal undulation and rapture so that it is suitable for gatherings of lahw and sin. It is haram for a singer to sing [ghina] and the listener to listen to it.
Office of Grand Ayatollah Sistani (may Allah grant him long life):
Singing (ghinā) is harãm: doing it, listening to it, or living of it are not allowed. The money received by the singer does not become his property. By “singing — ghinā,” we mean an amusing statement expressed in the tunes that are suitable for those who provide entertainment and amusement. In this prohibition, we should include the recitation of the Holy Qur’ãn, supplications (du‘ãs) uttered to the accompaniment of those tunes [that are used by the entertainers]. The prohibition of reciting other non-entertaining expressions —like songs intended to lift the morale [of fighters]— is based on compulsory precaution. As for music, it is not permissible to play or listen to music that is suitable for entertainment and amusement gatherings. [The crucial line is in it [music] being commensurate with the gatherings of entertainment and moral depravity.] Playing such music and receiving money for it are also haram and the money does not become the property of recipient. Teaching and learning it are haram and listening to a woman’s song with the intention seeking pleasure is not permissible.
Office of Grand Ayatollah Makarem Shirazi (may Allah grant him long life):
1. In any case, there is an objection (ishkal) to a woman singing singly.
2. As for the definition of ghinā and the philosophy of its prohibition, refer to book “180 Questions and Answers”, page 510 which is accessible on the Farsi web page under Works section.
3. Answered above.
Office of Grand Ayatollah Saafi Gulpaigani (may Allah grant him long life):
Generally speaking, all kinds of music which are played with instruments which are for joyful ecstasy (tarab) is haram. Ghinā means "prolongation and vibration of sound with variation of the pitch to such an extent that people may say that ‘he/she is singing’. It is also haram to listen to her.
An answer given to the above the question by Ayatollah Mahdi Hadavi Tehrani (may Allah grant him long life) is as under:
1. Ghinā is a song which makes a person go out of normal condition causing him sexual excitement. Generally such songs are commensurate with gatherings of entertainment and debauchery.
2. Ghinā is haram irrespective of whether the singer is a man or a woman.
3. Music accompanied with ghinā has no role in prohibition of ghinā.
4. If music makes a person go out of normal mood and causes him sexual excitement, it is haram. Such music is normally appropriate for gatherings of entertainment and debauchery. Such music is proven to be haram even if it is not accompanied with a son.
Related indexes:
Question 6185 (site: 6364) (What is meant by ‘evil’ in respect of Ghinā and Music?)
Question 10973 (Criteria with which to distinguish between halal and haram music in the West).
Link to Isteftaat Website (code: 1112)