[brandmeyer]

The reason the author's beamformer doesn't work very well may have nothing whatsoever to do with his implementation. A short-baseline microphone array won't be able to have good selectivity in the human hearing range no matter what you do. All synthetic aperture systems are fundamentally limited by the wavelength of the thing being sampled. You need an aperture many wavelengths wide in order to get a significant effect at any given frequency. The tiny two-mic device shown in the picture will only be an effective aperture in the near-ultrasonic range.

That's why commercially available phased array microphone systems that actually work are typically one to several meters wide.

[throwaway7767]

I understood his article such that he used the same laptop to test both his own beamforming algo as well as the google one. Since the google one seems to work very well, it seems likely that the limit is not hardware.

I'm actually very surprised that it works as well as it does, based on the sample recordings.

[brandmeyer]

Any claim that someone beat the diffraction limit should be viewed with the same level of skepticism as faster-than-light particles, engines that don't conserve momentum, perpetual motion machines, etc.