US Patent 10572534 Distributed coordinated recording

portable recording devices digitize audio signals and store the resulting digital audio samples locally. A master device periodically communicates a time marker and index value. Upon receiving a time marker from the master device, the recording devices latch their sample recording address occurring at that time, and store this latched address along with the received index value. Since the same index value is associated with recorded sample addresses occurring at the same time across all units, the shared index value provides a coordination means to later align the individual recordings, emulating a central multi-track recorder. Optionally, one of the portable recording devices can assume the additional role of master.