Eschew vibrato as a choir, and you risk the ignominy of uncovering all kinds of approximations in pitch, ensemble and inflection. While few groups can withstand such scrutiny, the Rodolfus ensemble can. It comprises of recent 'graduates' of conductor Ralph Allwood's famous Eton Choral Courses. Their expertise is obvious in the unaccompanied setting 'The Summer is Coming' which opens this recital: the purity and unanimity of the soprano monodies at the piece's beginning are later matched by the poised articulacy of the other voices, nailing tight, adjacent intervals pin-perfectly while maintaining the type of relaxed vocal production that betokens true class and technical quality. It's not just technical quality that's on offer here, however. The supple account of 'A Spotless Rose' is full of expressivity, as are the potentially mechanistic ululations of 'Sing Lullaby', where the shifting dynamic contours of the piece are traced in enviably organic fashion. Lots of work has been done on the weighting and sound quality of consonants: the choir's deftness and unobtrusive single-mindedness in this area adds an extra frisson of communication to even as brief a setting as 'God be in my Head'. Put simply, this disc has quality stamped all over it, and it's graced by Paul Andrews's exemplary notes.