The viola da gamba is, in contrast to the violin, essentially an introvert and soft-sounding instrument intended from the outset for small rooms. Since this fundamental peculiarity of the gamba was sel-understood and generally known at the time when the sound of all the string instruments was amplified (roughly from 1780), no attempt was made then - even though success seemed assured - to preserve the gamba for the new era of musical dynamics, the instrument sooner being dispensed with altogether. The essential features of the gamba’s tone were, however, not known any longer when it was rescued from oblivion at the beginning of this century. The reinforcement of tone that had not even been attempted a century earlier was therefore carried out at this time, thus robbing the instrument of its rnost important characteristics. There is no possibility of replacing the gamba by a modern instrument without upsetting the balance, unless of course one alters the entire instrumentation. It is very interesting to study in Bach`s chamber music how important or unimportant its realization in sound was to the composer, why a work has been conceived for just this instrument and no other. In any case, only a few generations before Bach the realization in sound was left almost entirely to the performer - a flute sonata for example could be played just as well on an oboe or a violin. Even many of Bach’s contemporaries still composed in this manner, and as long as the particular technical possibilities or the special tone ‘qualities of the various instruments were not deliberately used by the composer, this ‘ad libitum’ instrumentation is entirely legitimate. It is the purely tonal aspect of the instrument that Bach would seem to have employed most frequently; it appears to have been of particular importance to him. He thus uses a violino piccolo in the First Brandenburg Concerto without there being any technical necessity for it, without even exploiting all its possibilities, and similarly a ‘scordatura’ (retuned) violin for the G major Trio Sonata, BWV 1038 - in these cases he was clearly only concerned with the sound effect thus achieved. It is similar with his use of the viola da gamba, This instrument was, in Bach’s time, just in the process of being displaced from its pedestal as the most noble and distinguished of solo instruments, yet it was still in fashion, particularly in France. It seems as though the German composers regarded the gamba altogether differently to, for instance, the English or the French, who had made the gamba the most noble and highly developed solo instrument beside the lute and the harpsichord. (The Italians almost completely ignored it in favour of the violin, and wrote practically nothing for it.) With the exception of Kühnel and Schenk, who followed French models, the German composers such as Schmelzer, Kerll, Buxtehude, Telemann and Handel wrote technically for the gamba just as for any other melodic instrument; they were thus only concerned with its distinguished tone. Bach is entirely in this German tradition in his treatment of the gamba. His many solos for it in the passions and cantatas could, technically speaking, be performed just as well on other instruments; he here demands the gamba only on account of its special sound and the associations this evokes. The only exception is the gamha solo in the St. Matthew Passion (Bass aria “Komm, süßes Kreuz”) in which the gamba is used entirely in the manner of the French virtuosi. Bach`s three gamba sonatas are therefore gamba music in an entirely different sense to the sonatas and suites of, for instance, Marais and Forqueray. In Bach`s gamba sonatas the gamba and the harpsichord are absolutely equal partners who have strict three-part writing to perform in such a manner that the gamba performs one part and the two hands of the harpsichordist the other two. This technique of composition, which he also applied in his violin sonatas, was quite unusual and new for that period, Its special feature is not so much that the harpsiduord plays two fully written out parts instead of the usual continuo, but that the principal and subsidiary voices are equally distributed between the two instruments, the gamba thus frequently having to accompany the harpsichord.
Bach originally wrote the first of these three sonatas for an entirely different instrumental combination, namely as a trio for two flutes and basso continuo. Since it has also been recorded in this form on this disc, every listener can easily judge for himself how much the different instrumentation affects and influences the essential substance of the piece. In the flute version the two upper parts lie at the same pitch, the bass part being figured as in every triosonata, and performed with improvised harmonization. ln the gamba version the composer has transposed the part of the second flute an octave downward without any major changes to form a gamba part, the first flute and bass parts now forming the harpsichord part without the addition of any chords. The strict three-part writing naturally asserts itself far more strongly in this version than in the harmonized flute version. An interesting point that clearly demonstrates the significance of the Italian “tempo” indications in Bach’s time - namely that they are above all instructions for expression - is that the third movement of this sonata is designated "Andante” in the gamba version and "Adagio e piano" in the flute version.
The Second Sonata in D rnajoris probably the most characteristic of all of the gamba. Even though no chordal technique is required in it, the technical demands of the two Allegro movements are typical of the instrument. ln the second, third and fourth movements the strict three-part writing is abandoned in places in favour of a solo with continuo accompaniment, as a result of which the gamba comes more into the foreground as a soloist. Nevertheless, in order to underline the equality of the partners, the big gamba cadenza accompanied by the harpsichord in the last movement is preceded by a smaller one for harpsichord with gamba accompaniment. ln this sonata the bottom string of the gamba must be tuned down to contra-B if it is played on a six-string instrument.
The Third Sonata in G minor has an almost "concertante" character. lt is considerably more complex in its structure than the other two sonatas. The suspicion has been voiced in many quarters that it has been derived from a concerto. l would sooner regard it as an attempt to continue to its logical conclusion the principle begun in the Second Sonata, the contrast between continuo and obligato in the harpsichord part roughly corresponding to a concertante solo-tutti contrast. Three-part writing again prevails in the slow movement, though the bass here does not participate in the motif treatment of the two upper parts - the gamba and the treble of the harpsichortl. The Finale is in three parts, each being absolutely equal in importance as in the First Sonata.
The three sonatas are thus formally built upon one another: the First in pure three-part writing in which each of the three parts is absolutely equal in importance to the others; the Second already treats the gamba somewhat more in an idiom peculiar to itself the threepart writing being replaced in very few passages by solo writing with continuo accompaniment; in the Third the newly-found mode of writing with occasional “concertante” passages is further developed, this form being granted absolute precedence over the technique of the solo instrument. This sonata has thus been composed indeed with technical feasibility in view, but with no special consideration for technical characteristics peculiar to the gamba. The three sonatas are specifically intended by Bach for gamba and harpsichord. They can most easily be performed with musical plausibility on these instruments since the necessary balance between the parts is automatically present, and the garnba in particular stands out sufficiently from the harpsichord on the hand, and blends most happily with its tone on the other. Both the necessary unity and necessary diversity of tone can thus be sooner achieved here.