A microphone system for a boomless headset is disclosed, comprising a microphone array and a processing unit. The microphone array comprises Q microphones and generates Q audio signals. A first microphone and a second microphone are disposed on different earcups, and a third microphone is disposed on one of two earcups and displaced laterally and vertically from one of the first and the second microphones. The processing unit performs operations comprising: performing spatial filtering over the Q audio signals using a trained model based on an arc line with a vertical distance and a horizontal distance from a midpoint between the first and the second microphones, a time delay range for the first and the second microphones and coordinates of the Q microphones to generate a beamformed output signal originated from zero or more target sound sources inside a target beam area, where Q>=3.