The choir, in its origins in ancient Greece, served to explain what a solitary performer could not express and offered a mirror for audiences.

For the innovative theater company Carmina Slovenica, the concept of a choir also provides a broader political lens - to show how an individual can be swept up in the violence of a group.

The Slovenian ensemble has taken the concept to New York with performances of its intellectually challenging Toxic Psalms at Prototype, a festival of experimental opera whose third edition opened on Thursday.

Toxic Psalms features a chorus of some 30 women, bleakly dressed in dark gowns in a setting that evokes an imaginary world. In the course of an hour and a half, they touch on contemporary crises from abuses in the name of religion to the war in Syria.

"Toxic Psalms is a reflection of the spiritual anguish of today. Through music the project brings out the image of the brutality of man in the name of an idea - man killing for the glory of his 'psalms,'" says director Karmina Silec.

The choir performs elements of eight works including Sergei Rachmaninoff's All-Night Vigil, an allusion to Russian feminist punk rockers Pussy Riot who infuriated President Vladimir Putin and the Russian Orthodox Church with a satirical rendition of the sacred work.

But Carmina Slovenica keeps a deliberate ambiguity to the performances, without clear transitions between the pieces. The performers themselves do not stick to classical form and utilize vocal techniques including throat singing.

Silec refers to the performers as a "choregie", a vocal theater that brings together diverse music and spoken words in a way that encompasses multiple meanings and layers.

"Sometimes we simply don't want to narrow down a text, either (the) music or words, to one meaning only," Silec says. "I prefer the audience to experience their own journey, their own discovery. This freedom of their own imagination is very important."

Toxic Psalms, which the ensemble earlier staged in Berlin, also allowed discovery for the performers who were encouraged to try out material from what they saw in everyday life.

The chorus "manifests a collective body and as an organism it reflects a human desire to merge", she says.

"We played with the idea of how an individual acts in a crowd and what is its responsibility," she adds.

In an extreme example, Silec points to Hannah Arendt's often-cited "Banality of Evil" essay on the trial of Nazi war criminal Adolf Eichmann who did not take responsibility as an individual in organizing the Holocaust but rather claimed to be following orders within a group.

Silec also points to the more recent writings of Slovenian philosopher Slavoj Zizek, who said that a chorus "can take over from us and experience for us our innermost and most spontaneous feelings and attitudes".

Toxic Psalms serves as a "meditation on how little it takes to transform a completely innocent person into a criminal when he is guided by authority", Silec says.