I found out based on my research that there is quite a number of female choirs around the world who perform very well. Basically, female choirs have their own choral arrangement meant for their voices alone but I’ve heard of one female choir singing SATB arrangement which is so nice to hear. There are certain rules in choral singing. There should be no overlapping of voices but when i heard them sing, notes were not following the rules. This is musically beautiful but theoretically wrong.......what can you say about this?