The speed of sound in ethanol and benzene was measured over the temperature range of (253.2 to 353.2) K with pressures up to 30 MPa utilizing the double-path length pulse-echo technique. The speed of sound system was calibrated with pure water at temperatures between T = (274.15 and 353.15) K and ambient pressure. The reference equation of state for ordinary water represents the calibration data within the uncertainty of the equation of 0.005 %. The relative combined expanded uncertainty (k = 2) in speed of sound was 0.025 % for ethanol and 0.036 % for benzene. Comparisons of the measured speed of sound data for ethanol and benzene with values calculated from the equations of state as implemented as substance specific reference in the NIST REFPROP database are presented. Both equations do not represent the experimental data within their uncertainties. However, relative deviations of the experimental data from values calculated with the equations of state are within the uncertainties reported for the equations, which were 1.0 % for ethanol and 0.5 % for benzene. For ethanol relative deviations were between (-0.53 and 0.19) %, and for benzene relative deviations of (-0.43 to 0.37) % were observed.