From: Direction-of-arrival and power spectral density estimation using a single directional microphone and group-sparse optimization
Directivity pattern
\(\bf{[}c_0, c_1, c_2\bf{]}\)
Cardioid
[0.5, 0.5, 0]
Cardioid-A
[0.25, 0.5, 0.4]
Cardioid-B
[0, 0.5, 0.5]
Hypercardioid-2
[-0.2, 0.4, 0.8]