  Active noise control (ANC) systems are commonly designed to achieve maximal
sound reduction regardless of the incident direction of the sound. When desired
sound is present, the state-of-the-art methods add a separate system to
reconstruct it. This can result in distortion and latency. In this work, we
propose a multi-channel ANC system that only reduces sound from undesired
directions, and the system truly preserves the desired sound instead of
reproducing it. The proposed algorithm imposes a spatial constraint on the
hybrid ANC cost function to achieve spatial selectivity. Based on a six-channel
microphone array on a pair of augmented eyeglasses, results show that the
system minimized only noise coming from undesired directions. The control
performance could be maintained even when the array was heavily perturbed. The
proposed algorithm was also compared with the existing methods in the
literature. Not only did the proposed system provide better noise reduction,
but it also required much less effort. The binaural localization cues did not
need to be reconstructed since the system preserved the physical sound wave
from the desired source.
