Masked thresholds were obtained for ten frequencies between 125 and 8000 Hz at three different noise levels on five subjects. Threshold procedure was 4IFC, in which duration of the tone was 300 msec. Values of bothS/N0andE/N0(whereSis power of tone at MT,Eis energy of tone at MT, andN0is spectrum level of the noise) were calculated from this set of data. The results of the present study were compared to those of Hawkins and Stevens (1950) and those of Green, McKey, and Licklider (1959). The problem of converting a signal‐to‐noise ratio measurement into an indirect estimate of critical bandwidth is discussed.