Umetrix Voice compares each collected degraded speech sample against a reference speech sample in order to calculate the MOS. The reference audio files are stored in C:\Program Files (x86)\Spirent Communications\NomadUX\Audio Files:
PESQ NB = Narr_usasts_107dB.wav
PESQ WB = wide_usasts_10xdB.wav
POLQA NB = Narr_usasts_107dB.wav
POLQA WB = swb_ref_16kHz.wav