It is widely assumed that changes in open quotient (OQ) produce corresponding changes in H1*‐H2*, but empirical data supporting this relationship are scant. To provide such data, high‐speed video images and audio signals were simultaneously recorded from six speakers producing the vowel /i/ while varying F0 from high to low and voice quality from pressed to breathy. Across speakers, the observed relationship between OQ and H1*‐H2* was much weaker than generally assumed. Patterns of covariation also differed substantially from speaker to speaker. Estimation of harmonic amplitudes was complicated by difficulties in determining the frequency of F1 when F0 was high and by uncertainties regarding the F1 bandwidth in the presence of a persistent glottal chink. Use of analysis‐by‐synthesis allowed correction of formant values, but bandwidth estimation remains problematic and will be discussed further at the conference. [Work supported by NIH Grant DC01797 and NSF Grant BCS‐0720304.]