Kauffmann's first prelude to "Allein zu dir, Herr Jesu Christ" is a small treasure of contrapuntal writing. It has the chorale melody in the bass voice, while the other three voices accompany the chorale melody with the first phrase of the melody in imitation and in inversion. As short as it is, there is a lot going on in those 17 bars.
The recording was done with the Hauptwerk software and the sampleset, made by Voxus, of the Müller organ in the Sint Bavokerk, Haarlem (http://www.voxusorgans.com/en/product/haarlem).
Score available here: http://partitura.org/index.php/georg-friedrich-kauffmann-allein-zu-dir-herr-jesu-christ