Professionals have instruments that measure the precise period of the clock ticks that are heard, so the adjustment lever can be set accurately immediately.
With a computer (or with a smartphone), one could easily improvise an equivalent instrument, by recording the ticks with the microphone and displaying the tick period during adjustment.
With a computer (or with a smartphone), one could easily improvise an equivalent instrument, by recording the ticks with the microphone and displaying the tick period during adjustment.