An efficient, adaptive method of measuring loudness growth functions

This paper presents a new categorical loudness scaling procedure that differs from previously published loudness scaling procedures by (i) adaptively selecting a new set of levels for each new sequence, (ii) deriving levels that are equispaced on the loudness scale, and (iii) using a continuous scale with few labels. A major advantage of the adaptive procedure is that the individual dynamic range need not be measured prior to loudness testing. The adaptive procedure proved to be time efficient and to produce complete loudness functions from Not heard to Uncomfortably loud for normal hearing and hearing impaired subjects. The pattern of short-term and long-term reliability was similar to that reported for non-adaptive loudness scaling procedures. Three presentations produced a stable loudness function. Normative curves for one octave babble-noise at six test frequencies are presented and compared to normative data obtained with a selection of published categorical scaling procedures.