The masterpiece is the first A. Lange & Söhne model that sounds the hours, ten-minute intervals, and minutes. The acoustic sequence precisely reproduces the digitally displayed time whenever the striking mechanism is triggered with a pusher. The dial time is sounded with a low-pitched tone for each elapsed hour, a double tone for each elapsed ten-minute period, and a high- pitched tone for each elapsed minute.
To maximise the quality of the sound, the engineers calibrated the movement with the case, down to the smallest detail. The tuning process requires acute hearing and is performed manually to achieve harmony and reverberation of each gong separately and to assure perfect sonority in unison.
To assure that the repeater sequence is not prematurely interrupted due to the depletion of the mainspring’s power – in which case the watch would stop running as well – the striking mechanism can no longer be activated if the remaining power reserve is less than 12 hours. On the power-reserve indicator, this point is identified with a red mark. Because the mainspring powers the striking mechanism via the ratchet wheel, the number of minute repeater activations and their duration will influence the availability of the underlying power reserve of 36 hours.
With its eminently legible jumping numerals display, the ZEITWERK MINUTE REPEATER stands out as a paragon of eloquent design. The patented constant-force escapement delivers a uniform amount of energy during the entire power-reserve period. As the source of the switching impulses, it reliably controls the numerals display minute by minute.
A. Lange & Söhne’s ZEITWERK MINUTE REPEATER is the second model of the ZEITWERK family to be endowed with an acoustic time indication. With its unusual design, it represents a further milestone in A. Lange & Söhne’s impressive repertoire of innovative timepieces.