The project
The owner reported a subtle but consistent pitch wobble during long sustained passages, most audible on louder combinations — a classic symptom of an unstable wind supply rather than a tuning problem, since true tuning drift doesn't fluctuate within a single sustained chord. Inspection confirmed the main bellows leather had dried and lost enough elasticity to let wind pressure sag under sustained heavy demand. Both the main bellows and the two reservoirs feeding the manual divisions were fully releathered, restoring steady wind pressure under full-organ combinations.
Wind pressure was measured and logged before and after the releathering work, confirming pressure now holds within the instrument’s original factory tolerance under sustained full-organ combinations.