Human frequency following response to synthetic vowels
Sarah Stein Greenberg, James C. Smith, James T. Marsh, Warren S. Brown · The Journal of the Acoustical Society of America · 1978
Farfield recording of the frequency following response (FFR) to digitally synthesized vowels was undertaken in an effort to determine the role played by periodicity-based auditory mechanisms in the perception of speech. Stimuli consisted of five-formant vocoids with formant patterns corresponding to the vowels [ɪ], [ae], [a], [ɔ], and [U]. Stimulus duration was 48 ms and the rise/decay time corresponded to one (digitally simulated) glottal pulse. Two sets of vocoids were presented, one with a fundamental frequency appropriate to a male voice (125 Hz), the other with an F0 of a female voice (250 Hz). Spectral analysis of the signal-averaged FFR indicated that the largest component of the neural signal corresponds to the fundamental frequency of the stimulus. For certain vowels, local maxima in the FFR spectrum coincide with spectral peaks in the acoustic signal, particularly when the first formant lies below 500 Hz.