A REAL-TIME LPC-BASED VOCAL-TRACT AREA DISPLAY FOR VOICE DEVELOPMENT

This article reports the design and implementation of a graphical disp lay that presents an approximation to vocal tract area in real time fo r voiced vowel articulation. The acoustic signal is digitally sampled by the system. From these data a set of reflection coefficients is der ived using linear predictive coding. A matrix of area coefficients is then determined that approximates the vocal tract area of the user. Fr om this information a graphical display is then generated. The complet e cycle of analysis and display is repeated at approximately 20 times/ s. Synchronised audio and visual sequences can be recorded and used as dynamic targets for articulatory development. Use of the system is il lustrated by diagrams of system output for spoken cardinal vowels and for vowels sung in a trained and untrained style.