1. A method of reducing noise in a received signal, the signal being represented by a plurality of frames of data, each frame representing a plurality of samples of the received signal, the method comprising: determining a signal to noise ratio (SNR) for a first frame responsive to energy generated by a microphone, and responsive to the determination of a softSNR and a realSNR for the first frame; and determining a warped speech probability presence (SPP) factor for the first frame using a minimum mean square error (MMSE) calculation, which uses a SPP factor determined for a previous frame, the warped SPP factor for the first frame being determined using the signal to noise ratio determined for the first frame.