Multi-microphone noise reduction techniques for hearing aid applications go together with the
use of small-sized arrays. Considerable noise reduction can be achieved with such arrays, but at the
expense of an increased sensitivity to model errors or a priori assumptions. We evaluate the
robustness of the Generalized Sidelobe Canceller (GSC) and a Generalized Singular Value
Decomposition (GSVD) based optimal filtering technique both analytically and experimentally.
Especially in complicated noise scenarios, the optimal filter appears to be more robust.