Nevertheless, Quan họ is sung not only by twinning Quan họ people but also by others from other places. People can sing Quan họ at many locations; for example, they can perform it at houses at night on normal days, at temples on festivals, on hills, in the forest, along the street, at ponds, or on boat.In Quan họ singing, the male group is called liền anh, and the female group is called liền chị. Traditional Quan họ is pair singing without accompaniment. One of the pair is in charge of singing, leading the tune while the other sings as a secondary part. These two people have to be selected and trained to be in perfect harmony at the same timbre. In addition to pair singing, there is group singing, which is performed on congratulatoory and worshipping occasions. The male group sings in response to the female one. Four typical singing techniques of Quan họ are resonant, ringing, restrained, and staccato.