Biber’s “Mystery” or “Rosary” Sonatas are remarkable both for their musical quality and for their extraordinary use of scordatura – changing the violin’s normal tuning. Indeed, of the 15 sonatas, only the first (and the unaccompanied Passacaglia, added as a postlude) preserves the regular tuning; the other 14 all use a different mis-tuning. Why did Biber do this? The scordaturas make possible certain chords and passages that would not be feasible otherwise, but other aspects of playing become more difficult. If, as has recently been argued (by Daniel Edgar in The Encoding of Faith – PhD thesis, University of York: 2008), the Sonatas are intended as objects of meditation on the Mysteries of the Rosary (a series of events in the life of the Virgin) then the scordatura can represent a process of transformation – each tuning altering the violin’s sound and response, with the point of greatest strain coming as Christ’s sufferings reach their climax.

Are the Sonatas programme music? Daniel Sepec thinks so and his ideas about Biber’s descriptive intentions inspire his performance. Often these are persuasive – the fluttering of the Angel’s wings in the First Sonata (The Annunciation) or, in the Tenth Sonata (The Crucifixion), the hammering of nails into the Cross. His interpretation of the opening of the Eleventh Sonata (The Resurrection) as a sunrise is extremely poetic but I’m less sure about the deliberately ugly sounds in the Seventh Sonata (The Scourging of Jesus). In general, these are very fine-sounding performances. Sepec use three violins (to facilitate changes of tuning), all made by Jakob Stainer, known to Biber, and whose instruments were at one time valued even above Stradivari’s. The performances benefit greatly from the varied continuo group and often have a spacious, majestic character.

The Salzburg pitch seems to have been high in Biber’s time and I’d love to hear a recording that’s at, or above, modern pitch. But what emerges very clearly from these discs is the amazing range of Biber’s inspiration, brought out by playing that’s imaginative and deeply committed.