Prom Matinee 2: Academy Of Ancient Music, Cadogan Hall <br/> Prom 30: National Youth Orchestra, Royal Albert Hall, London

With its superb acoustic, Cadogan Hall was ideal for Richard Egarr to make his mark as new associate director of the Academy of Ancient Music. He began by reminding us that, when founded in 1726, the Academy's brief was to play music "more than 10 years old" - almost all performed music then was contemporary.

What we got was Bach and Mozart, "contemporary" in the 18th-century sense: two Brandenburgs, and Mozart's Divertimento in D major, and Adagio and Fugue in C Minor. With Brandenburg Four, one has readjust to the Academy's small, subtle sound. Egarr eased gently into the opening movement, and the pace became slower to allow the violinist Pavlo Beznosiuk to sail off into the empyrean; counterpointing with the violin in the second movement, the recorders of Rachels Brown and Beckett reminded one of the magic the instrument can achieve, particularly when descanting over the tender warmth extracted from the strings.

But in the Presto I wanted the pace and bite, the incisiveness of a modern ensemble, "authenticity" be damned: a feeling compounded in Mozart's Adagio and Fugue. In Brandenburg Five, on the other hand, Egarr's filigree flights on the harpsichord, and Beznosiuk's shuddering effects, paid off brilliantly.

Meanwhile, at the Albert Hall, the way the National Youth Orchestra (average age 17), under Sir Colin Davis (79), attacked Stravinsky's Symphony in Three Movements, you'd have said that it was one of our top bands. The brass came in with force, the pizzicato strings ratcheted up the tension, with the piano slicing through: immaculate. Continuing with Janacek's Taras Bulba, and winding up with Sibelius's Pohjola's Daughter and Seventh Symphony, the NYO presented a taxing programme with assurance.

BBC Proms to 9 September (020-7589 8212; www.bbc.co.uk/proms)