When she appears, the response feels almost primal, an anticipatory emotional release. Dressed in a black Southern Belle dress, Diamanda Galás is as much harbinger as woman-in-mourning, the unearthly power of her multi-octave voice a pressure valve for a host of long banished spirits. In the past she’s channelled those persecuted by the AIDS epidemic, victims of the Armenian massacre and more, and the laments, torch songs and petitions she airs tonight are all broadcast from the same state of restless, unrequited exile. Her voice ranges over ululations, snarls, vowels warped around the most pointed of accusations and a scoured and desiccated, necrotic rasp. Whether gouging the marrow out jazz classics, Jaques Brel, or the classic O Death – mangled in a manner that would impress Gunter von Hagens – she attacks her grand piano like a brutal interrogation. Diamanda Galás can make the most inaccessible of spirits talk, and heighten every sense to overload.