In a ``precueing'' experiment listeners may come to pay attention to a narrow cued frequency band and fail to monitor other frequencies. In the experiments a cueing tone was presented at some short delay before or after a target signal. In experiment 1, one of two cues at different frequencies was presented shortly before the single interval of a yes/no signal trial. Signal and cue were at the same frequency on 50% of the trials, so the cue was not informative as to signal frequency. Performance was analyzed separately for trials in which the signal occurred at the same frequency as the cue (valid trials) and when it was at a different frequency (invalid trials); the cue to signal delay varied. At short delays performance was enhanced on valid relative-to-invalid trials, but not at longer delays. In experiment 2, the cue was presented following the signal. In this post-cueing experiment subjects responded following the cue; the delay from signal to cue was varied. Performance was below chance performance on invalid trials but above chance on valid trials. These findings suggest that attended listening may modulate the processing of detected signals rather than modulate detection itself.