Suppression plays a crucial role in simultaneous masking. It is believed to cause a reduction of gain applied to the basilar-membrane (BM) response. Whether the reduction in gain in dB is constant across levels of the suppressed stimulus or is a constant proportion of the gain applied to the BM response for different input levels when the suppressor is absent, determines the slope of the response growth in the presence of the suppressor. The present psychophysical study measures how suppression of the response to a tone affects the growth of that response in the presence of a fixed-level suppressor. A forward-masking paradigm was used in which a short 4-kHz probe presented at a fixed level was masked by a longer duration 4-kHz masker. In the suppression condition, the same probe was masked by the 4-kHz masker presented together with a fixed-level 4.8-kHz suppressor. In both cases, the level of the masker necessary to mask the probe was estimated using a 3IFC tracking procedure. The task was repeated for different levels of the probe, which allowed for estimating suppression at different levels of the suppressed tone (masker). The results indicate a linearization of the BM response in the presence of a fixed-level suppressing stimulus. Different levels of a suppressor led to different slopes of the masking-growth functions (different slopes of the response to the suppressed masker), with higher-level suppressor producing a more linear response. Current models will be discussed in terms of their ability to predict the observed level effects.