One of the difficulties with the kol isha prohibition which I have heard is that it is difficult to understand why Hashem (and/or Chazal -- there are different opinions whether the prohibition is deoriysa or derabbanim) would deny all of us men the potential beauty of a woman's singing voice. While it is true that we can listen to our own wife's voice, it is quite rare for a woman to go through operatic voice training just to sing for her family and female friends. For pop music, it is understandable to me to avoid listing to those "artists" sing especially if one has ever seen any recent music video (don't!). In Jewish pop music, they get around not being able to have women sing by having young male children sing in their songs (which I personally find very annoying - sorry MBC).
However, for classical operatic singing, it can be very hard for some people to understand why we must be denied the beauty of a woman's voice.
Well, I came across this video recently which shows that a comparable tone can be produced from a male singing:
Although it is most likely not as good as a woman singing the same way, it at least shows that there is still access to that form of music even with the kol Isha restriction. This, like the shibuta fish (which tastes like pork), could be another example of the Midrash (Gemara? - I forget) which states that for everything Hashem prohibited to us, He gave us an alternative which is permitted.
