The system then determines the power spectral density of {HEAD ~ the audio signal} from the calculated power spectral density of {TAIL ~ the speech signal} 
The system then determines the power spectral density of { HEAD ~ the audio signal } from the calculated power spectral density of { TAIL ~ the speech signal }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL