This paper examines the acoustical effects of certain different laryngeal settings regulated by the shape of the larynx tube and hypopharynx on vowels. These effects are described using a two-by-two mass model, which is realized as two-layer two-mass models. The five Japanese vowels in different laryngeal settings were synthesized using the two-by-two mass model, with the area function of the vocal tract obtained by MRI. When the supraglottal structure of the larynx is constricted, the effects of the laryngeal ventricle resonance appear, and they depend on the extent of the constriction. In such cases, the inverse- filtered voices are not equal to the laryngeal sources.