Diplophonia reappraised

The acoustic structure of diplophonia was investigated spectrographically a nd in terms of perturbation measures, while the perception of diplophonia a mong other voice qualities was confirmed auditorily by trained listeners. R ecordings of pathological voices were presented to listeners for systematic evaluation, and narrowband spectrography was used to quantify the subharmo nics within each sample. Subharmonics strongly correlated with the percepti on of diplophonia, but occurrence was mostly intermittent, and structure wa s highly variable between samples. Uniquely among voice qualities identifie d perceptually, diplophonia was found to correlate positively with the numb er of subharmonics (irrespective of percentage of occurrence) and with pert urbation parameters measured separately. Exceptions to these group results indicated that diplophonia was perceived sometimes in the absence of subhar monic structure, and subharmonic structure was observed without a commensur ate perception of diplophonia. In light of these data, a less deterministic relation between diplophonia and subharmonic structure is proposed.