In Sardinia we can find a rich variety of ways to organize the sounds and change the tonality of the voices, using the vocal forms of expressions for different contexts, that can be both individual or collective. Some practices rely on monody (one voice), with or without musical accompaniment, others rely on the simultaneous singing of more individuals. There are different levels of difficulty, in monody the simplest forms were related to the personal life, like it happened for the chants of the cycle of life (anninnias, duru duru, attidus), the religious monodies (chanted rosaries) or work songs. Definitely more complex forms, are instead accompanied by musical instruments, like for example in the campidanese cantzoni a curba, or the elegant cantu a chiterra ("singing with guitar") in north Sardinia.
Polyphony, concentrated in the north central area of the island, features especially male choirs made by four voices, a system that recalls medieval and modern ecclesiastic models (like Fauxbourdon), which with a not fully historically documented spreading, helped to create at least to main types of choral singing. The first is tonally characterized by the guttural release of its two deep parts (bassu and contra), in the second one instead, those parts are emitted "di petto", from the chest.
There's no unique denomination for these two ways of singing; each community where they're practiced gives them an identity "mark": tenore, concordu, cussertu/ussertu/cuntzertu, cunsonu, tràgiu, coru. The local styles differ themselves for ways of release, tone, vocal range and repertories. While the guttural release is typical of the profane repertories (like the dance accompaniments), the one from the chest is largely used in the religious celebrations (like the rites during the holy week), but it's not uncommon for them to be used in both situations, like for example in several towns in the Baronia and Marghine areas.