Audiometry pure-tone durations are set by perception, not acoustic independence

Evidence

According to our previous analysis of spectral splatter, the 2-second tone has a spectral peak bandwidth of 1 Hz, whereas the spectral peak bandwidth of the 200-ms tone is 10 Hz. For both of these durations, the majority of stimulus energy is contained within a fairly narrow bandwidth around the signal frequency. Thus, ASHA’s recommendations for the durations of pure tones yield very little spectral splatter. No matter the audiometric frequency tested (e.g., 250 Hz or 500 Hz), these durations will yield pure tones that have no frequencies in common with other frequencies tested in the audiogram. We can then treat each frequency tested in the audiogram as being independent from the other frequencies from an acoustic standpoint. … In fact, from an acoustic standpoint, ASHA’s guidelines are extremely conservative. Even 20-ms pure tone would have a spectral peak bandwidth of 100 Hz, and thus the spectral spread of a 20-ms, 250-Hz tone used in audiometry would still provide a frequency representation independent from a 500-Hz tone. We can conclude, then, that ASHA’s recommendations of pure-tone durations are not primarily driven by acoustic principles. Rather, as we will see in Chapter 5 of this text, the pure-tone duration requirements are driven by perceptual principles. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 193

Categorization

• XREF: Links acoustic ‘spectral splatter’ theory to the audiology practice standard (ASHA guidelines) the reader is building understanding around.