The first choral prelude from Kehl's first volume of choral preludes I had not encountered before in other sources, is a prelude to the choral "Ein feste Burg ist unser Gott". It is a good example of Kehl's knack to write strong pieces using small means.
It is largely a bicinium, with only a few bars having more than two notes at the same time. The choral melody is played with the left hand, though the repeat of the first two phrases of the chorale melody is done with the right hand. The accompaniment for the right hand consists of rapid scales and broken chords in sixtheenth notes, the left hand plays a more sedate accompaniment in eighth notes. The emphasize the 'solidness' of the choral and of the prelude I play it with a plenum sound, based on 16 feet principals and reeds. Even though for the large part of the piece no more than two notes are sounding at the same time, with this registration it produces a lot of sound.
The recording was done with the Hauptwerk software and the sampleset, made by Sonus Paradisi, of the Schnittger organ in the St. Martini-kerk, Groningen (https://www.sonusparadisi.cz/en/organs/netherlands/groningen-st-martini.html).
Score available here: https://partitura.org/index.php/johann-balthasar-kehl-ein-feste-burg-ist-unser-gott
