Dynamic chiff
Blowing an organ pipe creates an effect known as chiff. This forms an essential component of the overall sound. In most electronic organs, chiff is created by computer simulation. The result ranges from poor to reasonable.
In Johannus organs, however, the original recording of organ pipes is used. Each time when a different key is pressed, the fundamental tone is preceded by chiff. When the same key of a pipe organ is pressed in quick succession, the air column remains inside the pipe. This causes part of the chiff to be lost, dependent on the speed of the note repetition.
Although this effect is typical of a pipe organ, it was always lacking in pipeless digital organs, because it was not technically feasible.
