“select a sound of one or three tones within the range of an octave
distribute the pitches between the keyboards (use each pitch only once)
select 3 – 31 stops from principals, flutes and reeds and distribute them evenly between the keyboards (do not use mixtures)
play the pitches and hold the keys down (e.g. with lead weights)
push the stop very slowly until you hear a change – then stop the movement, listen for a while and pull another register in the same way for a long time, only the rustle of the pipes remains”
For this recording the tone c was selected.