Autodirective audio capturing through a synchronized smartphone array

†Co-primary authors High-quality, speaker-location-aware audio capturing has tra-ditionally been realized using dedicated microphone arrays. But high cost and lack of portability prevents such systems from being widely adopted. Today’s smartphones are rel-atively more convenient for audio recording, but the audio quality is much lower in noisy environment and speaker loca-tion cannot be readily obtained. In this paper, we design and implement Dia, which leverages smartphone cooperation to overcome the above limitations. Dia supports spontaneous setup, by allowing a group of users to rapidly assemble an array of smartphones to emulate a dedicated microphone array. It employs a novel framework to accurately synchro-nize the audio I/O clocks of the smartphones. The synchro-nized smartphone array further enables autodirective audio capturing, i.e., tracking the speaker’s location, and beam-forming the audio capturing towards the speaker to improve audio quality. We implement Dia on a testbed consisting of 8 Android phones. Our experiments demonstrate that Dia can synchronize the microphones of different smartphones with sample-level accuracy. It achieves high localization accu-racy, and similar beamforming performance compared with a microphone array with perfect synchronization