Iwan Müller was born in Tallinn, Estonia, 30 years after Mozart. In his youth he was a clarinet virtuoso in the court orchestra of the Russian tsars in St Petersburg. Nevertheless, he was important for developing the clarinette omnitonique in 1809 using a new key mechanism and an increase in the number of keys to 13, which could produce all the notes of the chromatic scale over four and a half octaves. However, the Paris Conservatoire rejected his invention in favour of the Böhm clarinet.

His four concertos included here are sub-Mozartian but melodically quite attractive. Each opens with a commanding flourish from the orchestra before the soloist introduces the main lyrical theme. The Third Concerto (the first to be published) then offers a chirping secondary idea and the exposition brings an extensive cadenza and four variations, with more bravura cadenzas intervening. The Fourth Concerto is more restrained in its mood and scoring, its floridly operatic main theme followed by another wistful tune a four variations on a Russian folksong. The Fifth Concerto has only a single movement. It opens brusquely in a march rhythm, then sets off as a gay concert rondo, with each section changing style and ending with a tutti and a baby cadenza.

The Sixth Concerto is the finest of the group. After the traditional first movement with two contrasting themes, a Più lento is thematically linked to the preceding Allegro and the closing Bolero alla polacca. But finest of all is the Duo concertante, which reminds one of Weber, another single movement which moves from Adagio, quasi andante to Allegro molto, like a cantabile and cabaletta, with the two clarinets first singing a barcarolle and then wittily chattering together in thirds and sixths.

Friederike Roth is a most sympathetic exponent of this repertoire. She has a gentle dexterity and a sweet, firm timbre, and phrases with delicacy. She is expertly accompanied by Evan Christ, and the recording balance could hardly be bettered.