Carl Philipp Emanuel Bach's Double Concerto for Harpsichord and "Hammerklavier" is, if the date 1788 attributed to it is correct, the latest of the three works on this record. In any case it is the most original. Bach's second son, a lifelong experimenter, has intervened here - in the year of his death - in a process that must have occupied his attention very much as the greatest "expressive" master of the harpsichord and clavichord: the displacement of the "old" harpsichord by the "modern" "Hammerklavier" (long decided by 1788), and has easily come to terms with the situation. The solution he offers is both conservative and revolutionary at the same time. Once again the harpsichord is used quite naturally as a solo instrument (Mozart's great piano concertos were already written, but for the last, in 1788), but it is constrasted with its victorius rival in such a manner that the soundcharacter of both instruments and their possibilities of colour are effectively played off against one another. The principle of "concertare" has been transferred from a contest between tutti and solo to a rivalry between two principles sound production and playing. It is thus extended in a most ingenious fashion into a reflection of the historical competition between the two instruments, the harpsichord having more to say in the first movement, the piano displaying its greater melodiousness and the harpsichord its greater agility in the second and the piano not finally "setting the fashion" until the Finale. That the work falls between the epochs also reveals iteself in the basic character of its three movements in the nervously resilient rhythms of the "Hamburg Bach", the abrupt dynamic contrasts and the amazing harmonic changes, as well as in the already quite classical, free and colourful treatment of the wind, in the adventurous virtuosity of the outer movements and in the "cantilena" of the Larghetto, noble yet continually divided into finely-chiselled ornamentation.
Johann Christian Bach's Sinfonia Concertante, probably written during the composer's later years in London (ca. 1770-1781), is a genuine "concertante" symphony after the Parisian pattern, but completely filled with the melodie grace and gentle sensibility of this most "galant" of composers. Like many concertos, symphonies and chamber music works of the pre-classical period, this work has only two movements - a large-scale Allegro in free sonata form and an Italian Tempo di Minuetto. Both derive their substance from an ingratiatingly song-like and graceful melodic style that is essentially highly conventional. But the manner in which a concerto movement of the greatesr elegance and finesse of form is built out of these fashionable turns pf phrase, how a delicately rustic mood à la Watteau is distilled from the Italian minuet character consitutes the secret and the magic of the "London Bach", who realized more truly than any other composer of the 18th century the ideal (by no means to be despised) of a social are refined to the utmost. A greater contrast in the music of this century could hardly be imagined than that existing between this work and the Double Concerto of the eldest and most un happy of Bach's sons, Wilhelm Friedemann, which was presumably written around 1750-60. It is modelled on concertos by the father in that it is written for two solo harpsichords, and on the latter's C major Concerto in that the middle movement is a duet for the solo instruments without orchestra. Otherwise there is very little that recalls his father's style - most readily perhaps the heavy and resplendent orchestral writing with trumpets, horns and timpani, which is still treated entriely in the manner of a baroque tutti. Also baroque in the character of the first movement with its gloomy solemnity, its "sighing" suspensions and its brief chordal interjections by the tutti into the big, virtuoso solo passages; the harmony, on the other hands is strongly reminiscent of the style of his younger brother Carl Philipp Emanuel in its surprise effects. In spite of its key of C minor, yhe 3/8 Cantabile with its rapturous parallel thirds and sixths, written in three parts throughout, is more genial in its effect than this mighty first movement in the peculiar chiaroscuro colouring which had already struck his contemporaries in Friedemann's tyle. The Finale combines the baroque sound of the first movement with a thematic material that is already quite early classical, almost reminiscent of early Haydn, and in typical finale character. Even so, it is not yet able to find the carefree finale spirit, the "final dance" character of the early classical period; the gloomy, frequently fantastic-bizarre quality that dominated Wilhelm Firdemann's life just as much as his work is also clearly in evidence here.