Estimation of the voicing cut-off frequency contour of natural speech based on harmonic and aperiodic energies

We present a new algorithm for the automatic estimation of the voicing cut-off frequency (VCO), i.e., the frequency that separates the periodic low-frequency part from the aperiodic high-frequency part in voiced segments of natural speech. Starting from the power spectrum of a two pitch period speech frame, we define the VCO to be located at the frequency for which the sum of the periodic and aperiodic energy in the spectral band below and above that frequency respectively, is maximised. By formulating the problem in terms of a score function we are able to apply a dynamic programming based smoothing technique. Remarkably smooth and accurate VCO contours were obtained, despite the simplicity of the proposed algorithm. In a formal evaluation the algorithm compares favourably to two existing VCO estimation techniques.