SyncRecord

SyncRecord is an open-source Android application in the Recorder category. It turns a group of spatially distributed smartphones into a single ad-hoc microphone array for synchronized, multi-device audio acquisition. The application is intended for acoustic research, sound source localisation, and other work that requires recordings from several device locations without relying on a traditional hardware array.

A session begins with a master device, while other participants join using a unique alphanumeric session ID. The devices emit audible pseudo-random binary sequence signals, and cross-correlation of the captured audio is used to determine propagation delays between devices. This processing supports temporal alignment and estimates the distances between participating devices. Under the stated test conditions, recordings were aligned within 52 samples at 48 kHz, and inter-device distances were estimated within 14 millimetres.

SyncRecord provides a synchronized recording mode that combines device localisation with simultaneous capture of raw, unprocessed audio and produces time-aligned, multi-channel audio archives for further analysis. Its localise-array-devices mode determines the geometric layout of the devices without storing continuous audio streams. Calibration is performed through server-side signal processing, which estimates inter-device distances and corrects timing offsets automatically. The application can use a cloud-based demonstration server or a locally hosted server, with local deployment offering control over data handling and reduced latency.

For cloud sessions, audio data is deleted immediately after the session ends, and no user login is required. As an Android recorder distributed under an open-source license, SyncRecord fits users who need to inspect, use, or deploy a multi-device recording system within that platform. MirrorNest mirrors the official Android build directly on its own storage and scans it for malware before publishing.