1. Apparatus for processing an audio signal to acquire control information for a speech enhancement filter, comprising: a feature extractor configured for acquiring a time sequence of short-time spectral representations of the audio signal from a sequence of time portions of the audio signal, the sequence of time portions comprising a current time portion and another time portion configured for extracting, for each frequency band of a plurality of frequency bands and for each time portion in the sequence of time portions, a raw feature for the time portion of the audio signal from a short-time spectral representation corresponding to the time portion of the audio signal to obtain a first sequence of raw features for each frequency band for the current time portion and a second sequence of raw features for each frequency band for the another time portion, the another time portion being a past time portion or a future time portion with respect to the current time portion, and configured for combining, for each frequency band of the plurality of frequency bands, a raw feature in the first sequence of raw features in a frequency band for the current time portion and a raw feature in the second sequence of raw features in the same frequency band for the another time portion to acquire at least one feature in each frequency band of a plurality of frequency bands for a plurality of short-time spectral representations for the current time portion and the another time portion, the features for each frequency band of the plurality of frequency bands representing a spectral shape of the plurality of short-time spectral representations; and a feature combiner for combining the at least one feature for each frequency band for the plurality of short-time spectral representations and a raw feature extracted from only the short-time spectral representation corresponding to the current time portion of the audio signal using combination parameters predetermined by a training process to acquire the control information for the speech enhancement filter for the current time portion of the audio signal, wherein at least one of the feature extractor and the feature combiner comprises a hardware implementation.