Purpose: In this study, the authors investigated how well experts can adjust the settings of a commercial noise-reduction system to optimize the intelligibility for naive normal-hearing listeners. Method: In Experiment 1, 5 experts adjusted parameters for a noise-reduction system while aiming to optimize intelligibility. The stimuli consisted of speech presented in car cabin noise or babble at 5 different signal-to-noise ratios SNRs). In Experiment 2, the effects of processing with these settings were measured with 10 listeners undertaking an intelligibility test. In Experiment 3, the intelligibility of a broad range of settings was investigated with another 10 listeners to determine whether the experts' chosen settings could have been improved. Results: Low Cronbach's alphas indicated that parameter settings varied considerably within and across experts. For very low SNRs, mean proposed settings differed from those for higher SNRs. The different settings had no significant effects on intelligibility for naive normal hearing listeners. At high SNRs, the settings proposed by experts were found to deteriorate intelligibility. Superior intelligibility for naive normal-hearing listeners was achievable from settings other than the ones proposed by the experts. Conclusion: While attempting to enhance noisy speech, experts may propose settings that deteriorate intelligibility for naive normal-hearing listeners. (Contains 4 tables and 4 figures.)