Transmission Properties of the Vocal Tract—A Study Based on Analysis of Swedish Vowels and Consonants

Abstract

Spectrum measurements on Swedish vowels made at the L. M. Ericsson Telephone Company in Stockholm are reviewed in comparison with Bell Telephone Laboratories data on English vowels. A phonetic matching of similar sounds leads to good agreement in formant frequency data. The Swedish survey provides data on consonants, including stop consonant spectra. Calculations of vocal tract transmission have been made with the purpose of supplying a theoretical basis for these measured spectra. Transmission line theory has been used assuming a system of cylindrical resonators as in the recent work by H. K. Dunn of Bell Telephone Laboratories. Speech sounds other than vowels are investigated and dissipation and formant band width are included in the theory. In some cases, calculations for a consonant can be based on those for a vowel having the same resonator network, but with a primary sound-source acting at a position higher up than the larynx. In this case the vowel formants, corresponding to poles in the system function, will also appear in the consonant spectrum but with a modification caused by the presence of a number of zeros which do not occur for the vowel sounds. This results in a partial inhibition of some of the vowel formants in the consonant spectrum.