1. An apparatus comprising: an array having a plurality of microphones that produce a plurality of first signals in responsive to receiving a speech signal; a spectral analysis circuit that receives the plurality of first signals and generates a plurality of time-frequency spectra therefrom; a signal separation filter that receives the plurality of first signals or the plurality of signal spectra as inputs and generates an enhanced time-domain or frequency domain speech signal as output; and a hardware processor configured to: determine, from the plurality of first signals or the plurality of signal spectra, if a key phrase is present in the speech signal and, if the key phrase is present in the speech signal: align a template of the key phrase to a first time-frequency spectrum of the plurality of time-frequency spectra; determine a mask from the aligned template of the key phrase; apply the mask to the plurality of time-frequency spectra to provide a plurality of masked time-frequency spectra; determine acoustic parameters from the plurality of masked time-frequency spectra; and generate the coefficients of the source separation filter from the acoustic parameters; and configure the signal separation filter using the coefficients of the source separation function.