Estimating a sound signal in a known direction from a soundfield microphone recording

We present a method for estimating a sound or an early reflection from a room impulse response measurement made using a Soundfield microphone by adapting a technique for obtaining a highly directive microphone system using two cardioid microphones presented in [1] and a method for separating direct and ambient signals from stereo recordings presented in [2]. By assuming knowledge of the directional gains applied to the sound source of interest by a pair of coincident virtual microphones calculated from the Soundfield microphone, an optimal estimate of the desired sound can be obtained in the least mean square error sense. The performance of this method is evaluated using computer simulations and a real Soundfield microphone recording.