Practicing BWV 618--O Lamm gottes, Unschuldig

I came across this in the Orgelbuchlein and would like to work it up for Lent. I'm reading a bit about it, and some comments on Contrebombarde, and I want to practice it correctly. But wondering if there is something I should know about the cantus firmus, which is in the "alto" line apparently.

Is there something about changing manuals, or playing one hand on two manuals simultaneously, when playing the alto line? Or is it practiced with both hands on the same manual, and primarily playing the cantus firmus (alto line) with the right hand except occasionally with the left hand where impractical to play it with the right?


Jim

I got my answer. Apparently this piece can be played using the "thumbing" technique for the cantus firma (which is the alto line). Though not easy, one can use the thumb to play ths c.f. on a different manual. This enables the c.f. to be on a separate registration heard more distinctly.

interesting. I never considered that. It is also possible that if you just use your thumb on one manual the articulation is already sufficient to hear the voice.

I'm not sure which edition of BWV 618 you have, but in my Barenreiter edition, the cantus firmus is in the pedal, and the manual parts could be played on two separate manuals, as they are written independent of each other.

I think the primary cantus firmus starts in the pedal but is followed like a canon in the "alto" line.

Can someone correct me? Someone suggested that one could have a neutral (mabye a 8' principal) registration in the pedal, and a reed (clarinet or vox humanae?) in the alto "thumbed" line. Alternatively, one could possibly suggest two reeds--one in the pedal and one thumbed for the alto line, though I'm not sure how this would come off to the listener.

Hi Jim,

Just played this piece again today. The trick is to choose the right stop so the Alto is audible. I had to change from a flute to a Prestant to make that happen. The pedal can then also be played by a Prestant or possible by a read. The Alto indeed follows the Bas. This is a style more often used by Bach to express the need to follow Jesus and therefore should be clearly audible.