Absolute frequency measurements, with uncertainties as low as $2\mathrm{kHz}$ $(1\times {10}^{-11})$ , are presented for the ${\nu }_1+{\nu }_3$ band of ${}^{12}\mathrm{C}_2{\mathrm{H}}_2$ at $1.5\mu \mathrm{m}$ $(194–198\mathrm{THz})$ . The measurements were made using cavity-enhanced, diode-laser-based saturation spectroscopy. With one laser system stabilized to the $P\left(16\right)$ line of ${}^{13}\mathrm{C}_2{\mathrm{H}}_2$ and a system stabilized to the line in ${}^{12}\mathrm{C}_2{\mathrm{H}}_2$ whose frequency was to be determined, a Cr:YAG laser-based frequency comb was employed to measure the frequency intervals. The systematic uncertainty is notably reduced relative to that of previous studies, and the region of measured lines has been extended. Improved molecular constants are obtained.