Prom 26, Royal Albert Hall, London Susanna, Ilford Festival, Wiltshire Prom 21, Robert Albert Hall

Bach's B Minor Mass is too grand for liturgical use, but it was powerful, moving and dramatic at the Royal Albert Hall

Carolyn Sampson and Joelle Harvey in the operatic B Minor Mass (Laurie Lewis)

The six television cameras at the BBC Proms are models of butlerish discretion, unblinking and unobtrusive as they go about their work. Most of the time it is possible to ignore them. Except for one long-necked rebel whose hydraulic movements suggest a theatrical bent. Having posed as an inquisitive extraterrestrial during Pierre Boulez's abstractions for solo instruments and electronics last week, the renegade camera turned scholar on Thursday night, sidling up behind the principal double-bassist of The English Concert (Prom 26) as though to peer over his shoulder at the music of Bach's B Minor Mass.

Those watching the concert at home are more likely to have seen a player's-eye view of conductor and harpsichordist Harry Bicket than a close-up of the double-bass part. But if I were a long-necked camera, that's what I would focus on. The bass-line is the heartbeat of the B Minor Mass, from the incremental darkening of tone in the first fugal Kyrie to the brisk school-masterly tread of the Credo and Confiteor, the Italianate intensity of Et incarnatus est, the heartsore chromatics of the Crucifixus, the Brandenburg Concerto bounce of the Et resurrexit and the great sunburst of the Sanctus. Beneath the beating angel wings of oboes, trumpets and violins, and the high-altitude radiance of doubled sopranos and altos, chains of descending octaves from the basses describe an earthier sort of majesty. Too grand for liturgical use, this is an altarpiece in sound.

Bicket's thoughtful, spacious B Minor Mass was generously phrased and naturally paced, the work of a conductor who has moved from organ loft to opera house and absorbed the disciplines of both. Any special effects were Bach's: the abrupt contrast between the bright cross-rhythms and trilling trumpets of the Gloria and the milk-white flutes of Et in terra pax, the halo of muted violins around Joelle Harvey and Ed Lyons's Domine Deus, the collegiate jostle of natural horn, bassoons, organ, cello and bass in Matthew Rose's blustery Quoniam tu solus sanctus (the only performance in which I've been more worried about the singer than the horn player). Forty-two strong, and devoid of the selective ageism that makes some early music groups look like Take Your Daughter to Work Day, the English Concert Choir made a handsome, sophisticated sound; crisp in the dancing counterpoint of Pleni sunt coeli, rich and ripe in the long arc of Qui tollis peccata mundi. Carolyn Sampson's smiling Laudamus te (with violinist Nadja Zwiener) and Lyons's blissful Benedictus (with flautist Lisa Beznosiuk and cellist Joseph Crouch) sounded pure and easy in the packed hall, while Iestyn Davies's Agnus Dei was unforgettable: a point of stillness amid the beating wings, a moment of dramatic genius from a composer who wrote no opera.

Staged by Pia Furtado in the tiny cloisters of Iford Manor, Handel's oratorio Susanna is as disturbing as it is impressive. The first of three works to be written for the singer Giulia Frasi, who would create the role of Iphis in Jephtha and the title-role of Theodora, it recounts the apochryphal story of Susanna's molestation (here a balletic rape choreographed in the style of Pina Bausch) by two Elders who then accuse her of adultery, punishable by death. Directed from the keyboard by Christian Curnyn, with a nine-piece orchestra and a chorus of four, it is revealed as a powerful and inventive score, ill-deserving of neglect and, like Jephtha, deeply critical of blind faith.

Furtado draws on imagery from Margaret Atwood's A Handmaid's Tale to depict an ultra-religious sect in which women are subjugated. Rivalries and resentments flicker across the faces of chorus members of both sexes throughout the performance, adding texture and depth to a drama in which there is no place to hide, no time to coast. Mezzo-soprano Ciara Hendrick's grave, guileless face, clear tones and firm coloratura convey Susanna's vulnerability and strength movingly, while Christopher Lowrey sings the role of her husband Joacim elegantly. Sadly, he and Susanna's father Chelsias (Sam Evans) are adherents to the patriarchy and the boy prophet Daniel (Daisy Brown) is the only male to emerge with dignity. Handel's musical differentiation between the rapists is particularly interesting; the tenor (John McMunn) is a romantic fantasist, the bass (Simon Robinson) a thug, as though Polyphemus (from Acis and Galatea) had been split in two. For fans of bass-lines, Susanna is especially rewarding, with a pungent chromatic underpinning to its baleful chorus, "O Lord, how long?"

The Aldeburgh World Orchestra made its debut last weekend (Prom 21), with players from 35 countries performing under Sir Mark Elder. Led with impeccable poise by Avigail Bushakevitz, the strings gleamed, their sound well-nurtured, their attack athletic and precise. It was an odd programme. I've never been convinced by Britten's Sinfonia da Requiem (too sticky, too louche). Or the costive meandering of the Adagio of Mahler's uncompleted Tenth Symphony. Charlotte Bray's first Proms commission, At the Speed of Stillness, was all glitter and shimmer and dyspeptic brass, opulent and highly stylised. Elder's Rite of Spring was subtle and meticulous, more Champs-Elysées than pagan Russia: a showpiece for AWO's largely British trombonists – and that dancing, stage-struck long-necked camera.

'Susanna' (01225 448844) to 8 Aug

Critic's Choice

Kristjan Järvi gets groovy with Bernstein’s Mass (tomorrow), Semyon Bychkov embraces Ein Heldenleben (Wed), and Sir Mark Elder explores grief and guilt in Elgar’s The Apostles, (Fri), at the BBC Proms, Royal Albert Hall, London. Edinburgh International Festival opens with Delius’s A Mass of Life from the Royal Scottish National Orchestra and Sir Andrew Davis at the Usher Hall (Fri). Opera North’s new The Makropulos Case plays at the Festival Theatre from 11 Aug.