The prelude of this work is a beautifull, Mendelsohn-like, piece. It is not unlike the third part of Mendelsohn's fourth Sonata, even if that piece is in F major and this one in a minor. The left hand plays the melody of the chorale "Warum betrübst du dich, mein Herz", while the right hand provides a two part accompaniment. It is a beautifull, bittersweet piece. The fugue is based on a modulating theme that leads to a very chromatic piece, without it being too obvious. All in all a nice example of Richter's craftmanship in counterpoint and composition.
The recording was done with the Hauptwerk software and the sample set, made by Voxus, of the Van Dam organ (1832) in Tholen (http://www.voxusorgans.com/en/tholen).
Score available here: http://partitura.org/index.php/ernst-friedrich-richter-praludium-und-fuge-a-moll