The ability to extract information from relatively slow amplitude changes, the envelope, is a crucial aspect of auditory communication. The general question we address is how can this ability best be understood and described. One approach, the “modulation filterbank” model, postulates that there are filters that are selectively tuned to envelope frequency. This, essentially, is a translation of the well-documented notion of auditory spectral filtering into the domain of modulation frequency. We present data from experiments using complex modulators that suggest that a more useful approach may be to consider time-domain descriptions of envelope processing. The data seem incompatible with a simple modulation filterbank model but are easily understood, at least qualitatively, in terms of the local temporal structure of the envelope.

Another aspect we address concerns the role and nature of forward masking in envelope perception. More specifically, our data indicate that local envelope peaks affect later responses, i.e., the local peaks “forward mask” later occurring information. We argue that this forward masking can best be understood as a temporary reduction in sensitivity (adaptation), rather than persistence of excitation, and that these sensitivity changes should be incorporated into models of supra-threshold envelope perception. [Supported by Grant No. DC00683 from NIDCD.]