Several hearing loss simulators (HLS) have been developed to demonstrate the effects of hearing loss on auditory perception to normal hearing (NH) listeners, and to facilitate prediction of the perception of sound products by hearing impaired customers. This paper describes a real-time HLS based on an inverse, compressive GammaChirp (GC) filterbank, and how it was used to temporarily handicap NH listeners participating in a traditional notchednoise (NN) masking experiment (e.g. [1]) with a 2-kHz signal frequency. Sets of NN thresholds were obtain with a wide range of symmetric and asymmetric notches at two noise spectrum levels while participants listened to the sounds presented both with and without the HLS. The NN data were used to derive auditory filter shapes and input/output (IO) functions, which demonstrate that the HLS can simulate the elevation of pure tone threshold and the flattening of the input/output function commonly observed in sensory-neural hearing loss.