  A new version of a hearing impairment simulator (WHIS) was implemented based
on a revised version of the gammachirp filterbank (GCFB), which incorporates
fast frame-based processing, absolute threshold (AT), an audiogram of a
hearing-impaired (HI) listener, and a parameter to control the cochlear
input-output (IO) function. The parameter referred to as the compression health
$\alpha$ controlled the slope of the IO function to range from normal hearing
(NH) listeners to HI listeners, without largely changing the total hearing loss
(HL). The new WHIS was designed provide an NH listener the same EPs as those of
a target HI listener.The analysis part of WHIS was almost the same as that of
the revised GCFB, except that the IO function was used instead of the gain
function. We proposed two synthesis methods: a direct time-varying filter for
perceptually small distortion and a filterbank analysis-synthesis for further
HI simulations including temporal smearing. We evaluated the WHIS family and a
Cambridge version of the HL simulator (CamHLS) in terms of differences in the
IO function and spectral distance. The IO functions were simulated fairly well
at $\alpha$ less than 0.5 but not at $\alpha$ equal to 1. Thus, it is difficult
to simulate the HL when the IO function is sufficiently healthy. This is a
fundamental limit of any existing HL simulator as well as WHIS. The new WHIS
yielded a smaller spectral distortion than CamHLS and was fairly compatible
with the previous version.
