In two experimental replications involving a total of 17 otologically normal subjects, hearing threshold levels were observed that were from 2.6 to 7.1 dB less sensitive in the 125–1000 Hz frequency range, than those specified in ISO R226–1961. The published data from 12 additional threshold experiments conducted since 1933 were reviewed. Variables that could affect the data, such as free versus diffuse sound fields, pure tones versus 1/3‐octave noise band stimuli, psychophysical method, pulsed versus continuous stimuli, binaural versus monaural listening, age, sex, race, and otological rejection criteria, were analyzed. For frequencies from 50–1000 Hz and ages up to 35, the only corrections found to be necessary were for sound field conditions and binaural versus monaural listening. A second‐order polynomial regression line was fitted to the combined, corrected data. The resultant thresholds were 5–6 dB less sensitive than ISO R226 between 50 and 250 Hz, with the divergence dropping to +1.7 and −1.5 dB at 500 and 1000 Hz, respectively.