The praeambulum pedaliter on folio 34 of manuscript Ms Lynar B3 does not indicate a composer for this prelude. So it's anyone's guess who the composer might have benn. Based on the style of the composition however I am fairly certain it is not one of the named composer's in this manuscript. It's style is very different from the easy flowing style of martin Düben or the more monodic elegance of Martin Düben. It lacks the playfullness of Peter Hasse's prelude (yet to be published on this sit) and does not feature any of the imitative traits of Scheidemann's work. Nevertheless, it is a well composed piece with a well conceived development of dramatic impact. It starts in slow consonant movement and builds up to the more chromatic lines and rapid eigth notes movement of the final three systems. In my opinion a truly well composed piece that shows the hand the master. But which one?
Score available here: http://partitura.org/index.php/anonymus-praeambulum-pedaliter-2