A. TRUNCATION AND SUPEWOSITION*

G l o t t a l damping causes a truncation of formant amplitudes during the interval of glottal opening. This effect is especially apparent for high frequency F1 sounds. When the source i s defined as the true glot-tal flow, this requires the inclusion of F1 ripple in the source func-tion. Under conditions of small supraglottal damping and high F the F1 ripple may prevail in the later part of the glottal opening inrerval just before closure, thus affecting the strength of the main excitation. Conditions for such source-filter interaction have been studied theare-tically as w e l l as experimentally. It is concluded that formant am@-tude changes a t varying Fo are a function of both linear superposition and changes in the scale factor and spectrum of the glottal source. A t KTH, the Department of Speech Communication and Music Acoustics in Stockholm there are several projects underway directed towards the study of the human voice source. This report summarizes a few result