The theories of Professor Helga Thoene about the influence of chorales on Bach’s famous Chaconne have been explored before on disc, by the pure-voiced Hilliard Ensemble on the 2001 ECM album Morimur. This is odder, wilder and more successful. Lena Willemark is a Swedish folk singer, and her chorales are a solo-voice wail, plangent and moving, that cuts across Cecilia Zilliacus’s admirable violin like an echo from a ritual past. Bach lies behind the other pieces: too literally in Svante Henryson’s Sonata, more subtly in Sven-David Sandström’s highly original Dansa, where voice and violin intertwine and for one movement a second violin joins the evocative texture with Bach quotations.