Vocal tract configurations. ND denotes the no duct, or open jet, case. DL2 and DR2 denote the extreme left and right vocal tract offset cases (±4 mm) without the false folds, respectively, DL1 and DR1 denote the left and right offset cases (±1.5 mm), respectively, and DC denotes the symmetric vocal tract case, all without the false folds. FL, FC, and FR denote cases with false folds and the vocal tract positioned to the left (−1.5 mm), center, and right (+1.5 mm), respectively, of the vocal folds.