In his prelude to "Jesum lieb ich ewiglich" Sorge employs the technique of the canon. Each phrase of the chorale melody is canonically answered in the bass of in the alto voice. The accompaniment in the alto voice is played on the Bovenwerk of the Tholen sample set (Fluit Dolce and Viola di Gamba). The 8-feet stops on the other two manuals were to loud in my opinion to serve as a balances solo stop. So I resorted to the Quint 3' of the Hoofdwerk, played one and a halve octave lower. It's the first time I use a Quint as a solo voice. It works out rather nicely, I think.
Score available here: http://partitura.org/index.php/georg-andreas-sorge-jesum-lieb-ich-ewiglich