An apparatus for generating one or more audio output channel signals depending on two or more audio input channel signals, wherein each of the two or more audio input channel signals comprises direct signal portions and ambient signal portions, wherein the apparatus comprises: a filter determination unit for determining a filter by estimating first power spectral density information and by estimating second power spectral density information, wherein the filter depends on the first power spectral density information and on the second power spectral density information, and a signal processor for generating the one or more audio output channel signals by applying the filter on the two or more audio input channel signals, wherein the one or more audio output channel signals depend on the filter, wherein the filter determination unit is configured to estimate the first power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on said audio input channel signal, and the filter determination unit is configured to estimate the second power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on ambient signal portions of said audio input channel signal, or wherein the filter determination unit is configured to estimate the first power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on said audio input channel signal, and the filter determination unit is configured to estimate the second power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on the direct signal portions of said audio input channel signal, or wherein the filter determination unit is configured to estimate the first power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on the direct signal portions of said audio input channel signal, and the filter determination unit is configured to estimate the second power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on the ambient signal portions of said audio input channel signal. a filter determination unit for determining a filter by estimating first power spectral density information and by estimating second power spectral density information, wherein the filter depends on the first power spectral density information and on the second power spectral density information, and a signal processor for generating the one or more audio output channel signals by applying the filter on the two or more audio input channel signals, wherein the one or more audio output channel signals depend on the filter, wherein the filter determination unit is configured to estimate the first power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on said audio input channel signal, and the filter determination unit is configured to estimate the second power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on ambient signal portions of said audio input channel signal, or wherein the filter determination unit is configured to estimate the first power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on said audio input channel signal, and the filter determination unit is configured to estimate the second power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on the direct signal portions of said audio input channel signal, or wherein the filter determination unit is configured to estimate the first power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on the direct signal portions of said audio input channel signal, and the filter determination unit is configured to estimate the second power spectral density information by estimating, for each audio input channel signal of the two or more audio input channel signals, power spectral density information on the ambient signal portions of said audio input channel signal.