About the so called “resonance tubes” used in Finnish voice training practice: An electroglottographic and acoustic investigation on the effects of this method on the voice quality of subjects with normal voice

Abstract

Phonation into narrow glass tubes is used by some Finnish speech therapists and voice trainers for the treatment of phonasteny. The purpose of this study was to find out how the tubes affect the voice quality of normal subjects and whether the effect is related to the length of the tube or the fundamental frequency for speech range and modal register phonation. Two female subjects produced close vowels /i:, y:, u:/ and phonated into the tubes of 26, 27 and 28 cm in length at every semitone in the range of e-e1 (164–330 Hz). The results of electroglottographic and acoustic analyses (including measurement of spectral slope and signal-to-noise ratio) suggest that the tubes tended to improve the voice quality especially at the middle of the speech range. At high speech range the tubes made phonation more difficult. Neither the analyses nor the subjects' comments disclosed any systematic differences between the tubes at any fundamental frequency studied.