Binaural loudness summation for speech presented via earphones and loudspeaker with and without visual cues.

Preliminary data [M. Epstein and M. Florentine, Ear.

Testing the binaural equal-loudness-ratio hypothesis with hearing-impaired listeners.

The primary purpose of the present experiment was to test whether the binaural equal-loudness-ratio hypothesis (i.e., the loudness ratio between monaural and binaural tones presented at the same Sound Pressure Level, SPL, is independent of SPL) holds for hearing-impaired listeners with bilaterally symmetrical hearing losses.

Binaural loudness summation for speech and tones presented via earphones and loudspeakers.

Objectives: Literature reviews of binaural loudness summation assume nearly perfect summation (i.e., a tone presented binaurally is assumed to be twice as loud as the same tone presented monaurally).

Loudness growth in individual listeners with hearing losses: a review.

This letter reanalyzes data from the literature in order to test two loudness-growth models for listeners with hearing losses of primarily cochlear origin: rapid growth and softness imperception. Five different studies using different methods to obtain individual loudness functions were used: absolute magnitude estimation, cross-modality matching with string length, categorical loudness scaling, loudness functions derived from binaural loudness summation, and loudness functions derived from spectral summation of loudness. Results from each of the methods show large individual differences.

A test of the binaural equal-loudness-ratio hypothesis for tones.

It is well known that a tone presented binaurally is louder than the same tone presented monaurally. It is less clear how this loudness ratio changes as a function of level. The present experiment was designed to directly test the Binaural Equal-Loudness-Ratio hypothesis (BELRH), which states that the loudness ratio between equal-SPL monaural and binaural tones is independent of SPL.

Effect of adaptive psychophysical procedure on loudness matches.

Large variability in equal-loudness matches has been observed across studies. The purpose of the present study was to gain insight into the extent to which this variability results from differences in psychophysical procedures and/or differences among listeners. Four adaptive two-interval, two-alternatives-forced-choice procedures were used to obtain equal-loudness matches between 5- and 200-ms 1-kHz tones as a function of level for each of six normal listeners.

Monaural and binaural loudness of 5- and 200-ms tones in normal and impaired hearing.

The difference in level required to match monaural and binaural loudness of 5- and 200-ms tones was measured for listeners with normal and impaired hearing. Stimuli were 1-kHz tones presented at levels ranging from 10 to 90 dB sensation level. Sixteen listeners (eight normal and eight with losses of primarily cochlear origin) made loudness matches between equal-duration monaural and binaural tones using an adaptive 2AFC procedure.

Reaction time to 1- and 4-kHz tones as a function of sensation level in listeners with normal hearing.

Objective: Measures of reaction time (RT) near threshold have been used to indicate whether listeners with hearing losses of primarily cochlear origin experience greater loudness at elevated thresholds than at normal thresholds. These measurements have been based on the assumption that RTs near threshold are not affected by stimulus frequency in the 1- to 4-kHz range. The present study tests this hypothesis.

Loudness of brief tones measured by magnitude estimation and loudness matching.

McFadden [J. Acoust. Soc.

Effect of masker-fringe onset asynchrony on overshoot (L).

The study examines how overshoot is influenced by masker-signal onset asynchrony when the masker contains frequencies above or below the signal frequency. Masked thresholds were measured for a 2-ms tone at 5 kHz. The measurements were made in a reference condition with a narrow center-band (CB) noise masker (4590-5464 Hz), and in conditions with either a low-fringe (1900-4590 Hz) or a high-fringe noise band (5500-11 000 Hz) added to the CB.

A test of the equal-loudness-ratio hypothesis using cross-modality matching functions.

This study tests the Equal-Loudness-Ratio hypothesis [Florentine et al., J. Acoust.

Inferring basilar-membrane motion from tone-burst otoacoustic emissions and psychoacoustic measurements.

The amplitude of otoacoustic emissions, which arise on the basilar membrane, is assumed to be proportional to basilar-membrane motion. It should then be possible to assess basilar-membrane motion on the basis of otoacoustic emissions. The present study provides support for this possibility by comparing basilar-membrane motion inferred from emissions to that inferred from psychoacoustic measures.

Spectral loudness summation and simple reaction time.

The present study evaluates the relation between loudness and simple reaction time (RT). Loudness matches between a narrowband noise (125 Hz wide) and a broadband noise (1500 Hz) were made at levels from near threshold to near 100 dB SPL. Over a similarly wide range of levels, RT to each of the noise bands was also measured.

The effects of window delay, delinearization, and frequency on tone-burst otoacoustic emission input/output measurements.

Tone-burst otoacoustic emissions (TBOAEs) are a potential tool for objectively examining cochlear activity in humans. However, their use requires knowledge of how the TBOAE input/output depends on measurement and analysis paradigms. The present experiment examined the effect of variations in response-window timing, response delinearization, and local changes in stimulus frequency on TBOAE input/output measurement.

Interactions between test- and inducer-tone durations in induced loudness reduction.

A tone usually declines in loudness when preceded by a more intense inducer tone. This phenomenon is called "loudness recalibration" or "induced loudness reduction" (ILR). The present study investigates how ILR depends on level, loudness, and duration.

A comparison of psychophysical procedures for level-discrimination thresholds.

Five different psychophysical procedures were used to measure level-discrimination (also called intensity discrimination) thresholds for 1-kHz tones at two levels (30 and 90 dB SPL) and two durations (10 and 500 ms). The procedures were the classic transformed up-down staircase method with a two-alternative forced-choice (2AFC) paradigm (UPD), 15- and 50-trial implementations of the method of maximum likelihood (MML) with a cued yes-no paradigm, and 18-trial implementations of ZEST using both cued yes-no and 2AFC paradigms. Results obtained from nine normal listeners show that estimates of level-discrimination thresholds for the four conditions are similar across all five procedures when different points of convergence are accounted for.

Perceptual weights in auditory level discrimination.

Perceptual weights in level discrimination (also called intensity discrimination) were determined for 3-, 7-, 15-, and 24-component tone complexes with flat spectral envelopes using a correlational paradigm. Each frequency component was randomly and independently perturbed in level oneach presentation. For the target interval, frequency-component levels were additionally increased by the level increment to be detected, deltaL [= 201og10((p + deltap)/p), where p is pressure].

Growth of loudness in listeners with cochlear hearing losses: recruitment reconsidered.

This article examines how loudness grows with increasing intensity near threshold in five listeners with hearing losses of predominantly cochlear origin. It provides evidence against the pervasive and long-held notion that such listeners show abnormally rapid loudness growth near their elevated thresholds. As in a previous study for listeners with normal hearing, loudness functions near threshold were derived from loudness matches between a pure tone and four- or ten-tone complexes using a simple model of loudness summation.