A real-time hearing loss simulator (HLS) based on an inverse, compressive, GammaChirp (GC) filterbank has been developed. This presentation will describe the algorithm used for simulation and will further present data from several previous experiments to illustrate how and why this HLS can be used for. Overall, the simulator is efficient to simulate the effect of hearing impairment on audiograms, on notch noise data (auditory filters), on input/output cochlear functions, on speech in noise intelligibility and on alarm detection in noise when wearing a hearing protector. However, the HLS failed to simulate the effect of a strong hearing impairment for high level sounds (alarm detection in a background noise displayed at 86 dBA). This limitation will be further discussed.