Morrison, Geoffrey2015-12-100167-6393http://hdl.handle.net/1885/65271Two procedures for the calculation of forensic likelihood ratios were tested on the same set of acoustic-phonetic data. One procedure was a multivariate kernel density procedure (MVKD) which is common in acoustic-phonetic forensic voice comparison, and the other was a Gaussian mixture model-universal background model (GMM-UBM) which is common in automatic forensic voice comparison. The data were coefficient values from discrete cosine transforms fitted to second-formant trajectories of /a/, /e/, /o/, /a/, and // tokens produced by 27 male speakers of Australian English. Scores were calculated separately for each phoneme and then fused using logistic regression. The performance of the fused GMM-UBM system was much better than that of the fused MVKD system, both in terms of accuracy (as measured using the log-likelihood-ratio cost, Cllr) and precision (as measured using an empirical estimate of the 95% credible interval for the likelihood ratios from the different-speaker comparisons).Keywords: Coefficient values; Credible interval; Empirical estimate; Forensic voice comparison; Formant trajectory; Gaussian mixture model-universal background models; GMM-UBM; Kernel density; Likelihood ratios; Log likelihood; Logistic regressions; Male speakers; Acoustic-phonetic; Forensic voice comparison; GMM-UBM; Likelihood ratio; Multivariate kernel density201110.1016/j.specom.2010.09.0052016-02-24