Abstract: A signal pre-processing apparatus for processing signal such that the signal is selectively adjusted for gain and equalization based upon a plurality of parameters predetermined by a noise reducing means. The present invention is a method and apparatus for substantially reducing undesirable noise components of speech signals in speech processing without necessitating added hardware, complexity, or sacrifice in speech signal integrity. In particular, background noise is reduced by means of frequency transformation and modification thus greatly enhancing speech quality without significantly affecting the reconstructed speech. By estimating the noise spectrum continuously from the input signal, the present invention permits modification of the frequency response of the input signal thus reducing the effect of the noise components of the input signal.