We measured the ability of observers to detect an increment in the intensity of a 100-ms 1000-Hz sinusoid under two conditions. In the first condition, the observer heard single 1000-Hz sinusoids —either the standard or the standard plus the increment. In the second condition, ten other sinusoids were added to the 1000-Hz sinusoid with frequencies ranging from 200 to 5000 Hz. These additional components were equal in intensity to the standard and the frequency ratio between successive components of the 11-component complex was 1.38. The basic task for each condition was the same, to detect an increment in the 1000-Hz component. The increment was easier to detect in the complex spectrum or “profile,” presumably because the additional components allow one to make simultaneous comparisons among the different components. Only a successive comparison between the 1000-Hz components was possible in the single sinusoid condition. The improvement is as much as 10 dB for some observers and conditions, when expressed in terms of the signal relative to the standard. [Work supported by NIH.]