Input-output (I/O) functions of hearing aids were measured in response to a 2000 Hz tone burst, having 0.5 ms rise/fall time and 10 ms duration. Findings indicated that the steady-state output limitation characteristics of hearing aids cannot be estimated from their onset responses. (Author/DB)

Three hearing aid manufacturers provided custom full-shell in-the-ear hearing aids designed for maximum acoustic gain for each of three hearing-impaired adults. Full-on coupler gain curves were similar across all nine hearing aids, with individual differences producing substantial variance in insertion gain across hearing aids. (Author/DB)