Beamforming is intelligent spatial filtering which extracts
only target signals from noisy environment using
microphone arrays. Fixed beamforming is simple and
easy concept but does not show good performance in
real noisy situations. As an adaptive method, Frost
beamforming which has error correction feature is a good
alternative. Furthermore, to adjust elements of each
filterbank such as filter length and learning rate,
Quadrature Mirror Filter (QMF) is implemented. The
filter lengths and learning rates of the beamformer are
optimized in each band. The performance is evaluated by
Signal to Noise Ratio (SNR) gain and Bark scale
Spectral Distortion (BSD).