Undoing nicking in old flue organ pipes - Is it possible to return to the original sound?

Paper in proceeding, 2007

Nicking is a well-known voicing adjustment used by organ builders to control the dynamics of the jet in flue organ pipes. However, it has not always been used and we know that nicks found in many old pipes were applied subsequently, i.e. when this voicing technique became common. Thus in the attempt of returning to the pipe’s original sound it would be necessary to remove these nicks. It then arises the ethical question to what degree one could succeed in obtaining the original sound. To investigate the possibilities and limitations of undoing nicking adjustments a set of flue organ pipes was manufactured. Great effort was taken to craft them identical in geometry and with identical voicing. Then a different type of nicks was applied to each pipe, keeping only one reference pipe unaltered. In a second step the nicking was undone using some of the known techniques for this purpose. The process was documented in different ways, including recordings of each pipe’s sound after each working step. Audio data were compared subjectively (listening) and analytically. Preliminary results indicate that even though the overall sound character of a pipe without nicks can be regained, exactly reversing the process seems not possible.