Today we conclude Prof Adrian Fourcin’s series.
6. In Conclusion
The main contributions to voice quality analysis which are presently made possible by Laryngograph type approaches come from the special physical properties of the equipment and the very close relation between the signal and the processes of voice generation and control.
• Non-invasive sensing gives acceptable access to a wide range of speaker populations
• Response primarily only to vocal fold contact provides an effectively unrivalled accurate basis for larynx frequency measurement.
• Acoustic noise immunity is a special advantage for data gathering in many work environments (including the hospital voice clinic), and in the quiet this facility gives an extremely useful basis for frication detection.
• The duration of vocal fold contact is represented in the laryngograph waveform with sufficient accuracy to give a basis for closed quotient comparison.
The particular examples discussed above have tended to concentrate on the links which can be made between objective measurement using Lx type signals and the use of auditory dimensions of voice quality description. This is an increasingly important area of development. The measurement techniques described are able to provide one way of escaping from the current clinical bias towards the utilisation of data [sustained vowels for example] not so much because it is important in real life as because it is convenient in use for the investigator. The two-minute speech samples (of Sp & Lx) used are easy to obtain and representative of major speech factors such as onset, offset, register change and vocal tract/larynx interactions which are largely absent from sustained samples.
Acknowledgements
In addition to Mr Julian McGlashan and Beverly Towle and their colleagues at QMC Nottingham and Dr Elisabeth Fresnel of the Laboratoire de la Voix, Paris, it is a pleasure to acknowledge the laryngograph, stroboscopic and analytic resources which have been developed by Colin Bootle, Xinghui Hu and David Miller at Laryngograph Ltd. and used for the figures and discussions in this paper.
Prof Adrian Fourcin
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