A spatial filter unit (200) for converting a first input signal (U) comprising input samples, into an output signal comprising output samples, is disclosed. The spatial filter unit (200) comprises: a coefficient-determining means (106) for determining a first filter coefficient; and an adaptive filtering means (104) for computing a first one of the output samples on basis of a first one of the input samples and the first filter coefficient. The coefficient-determining means (106) are arranged to determine the first filter coefficient on basis of a second input signal (Y) being correlated to the first input signal (U).