The specification of the distracter voices forms an elliptical spoke pattern in the GPR-VTL plane. The ordinate has been compressed by a factor of 1.5 to illustrate the relationship between GPR and VTL used in the experiment. It is this, that makes the ellipses appear circular. The pitch of the distracter voices varied from 137 to 215 Hz, and the VTL varied from 11 to 21 cm. The target voice is in the center of the spoke pattern with a pitch of 172 Hz and a VTL of 15 cm. In the text, points in the plane are described in terms of their radial displacement from the target (a vector distance). For convenience, they are arbitrarily numbered 1–7 where 1 is closest to, and 7 is farthest away from, the reference voice in the center. The RSD1.5 values for spoke points 3, 5, and 7 are shown; see Table I for the complete specification. Some of the distracter voices were used in the extended SNR experiment; they are marked with circles. The gray areas show the region of the plane occupied by 95% of male and female speakers in the population reported by Peterson and Barney (1952), and modeled by Turner et al. (2009).