Bach also specified in his “Draft” the kind of orchestra he considered optimal, suggesting the following instruments:

2-3 first violins second violins
2 first violas
2 second violas
2 cellos
1 violone
2 or 3 oboes
1 or 2 bassoons
3 trumpets and
1 timpanist

The stipulation of having more than one string instrument per part, supported as well by oboes and bassoons, may have been deemed important by Bach for certain of his Leipzig works such as the St. Matthew Passion. Many of Bach’s orchestral works, however, such as the Brandenburg Concertos and the two orchestral Suites in D, seem to have been realized by single string instruments (i. e. with one string per part). Again, the evidence lies in the surviving part books, which Rifkin has examined in detail5.

Bach’s stipulation of a violone is of interest. This was most likely a contrabass violin-family instrument. It was distinguished from the cellos in a number of Bach’s scores. In the Brandenburg Concerto No. 1, for example, the bass line is played by a “fagott” (bassoon), a “violoncello,” and “continuo e violone grosso.” Here and in the other Brandenburg Concertos the violone mostly doubles the cello, presumably an octave lower. Bach’s request for trumpets and timpani reflects his use of these instruments for certain of his more festive movements, as for instance in the opening of the Christmas Oratorio or in certain movements in the Mass in B minor.

The Organ

Bach, among the great organists of his time, both performed on and conceived music for a wide variety of organs, ranging from the North German Schnittger to the central German Silbermann. Many of the organs on which Bach played have been identified and their specifications considered6.

Of some interest is Bach’s memorandum of 1707 for changes or compomises to be made on the Mühlhausen organ, including his suggestion of a manual viola da gamba (replacing a Gemshorn) and in the pedals of a 16’ Posaune and 32’ Subbass. He also singled out the importance of a full wind supply. These stipulations could have been made for the sake of modernizing an out-of-date instrument, but they also probably provide clues concerning Bach’s own preferences7.

A pupil of Bach, Johann Agricola, mentioned the composer’s predilection for reed stops, his insertion of brightly colored stops for congregational singing, and his propensity to call upon the quieter stops to provide a continuo background. Agricola considered the 16’ querflöte and 8’ gamba to be especially effective for runs and arpeggios. He also recommended a 16’ plenum, as had also the 18th-century theorists Adlung and Mattheson. But going beyond these writers, Agricola also allowed for an added Trompete as part of the plenum. He was especially partial to the Cornett, which he referred to as Bach’s most treasured combination stop. Aside from this, he defended the simultaneous combination of 8’ registers, but opposed the use of 4’ in a lower register or of “open” registers, e. g. 16’ + 4’ or 8’ + 2’8.