This paper presents a new robust microphone array processing technique to enhance speech signal under the influence of noise and jammer(s). The new structure comprises of two soft-constrained subband beamformers and a non-coherent processing technique.Essentially the first beamformer enhances the desired speech signal in a specific constrained region. The residual interference in the beamformer's output is then spectral subtracted using the estimated interference from the secong beamformer. Evaluations in a real office environment show higher interference suppression compared to those obtained using the soft constrained beamformer only. Most importantly, this is achieved with negligible expense on target signal distortion.