Fine structure of hearing threshold and loudness perception

Hearing thresholds measured with high-frequency resolution show a quasiperiodic change in level called threshold fine structure (or microstructure). The effect of this fine structure on loudness perception over a range of stimulus levels was investigated in 12 subjects. Three different approaches were used. Individual hearing thresholds and equal loudness contours were measured in eight subjects using loudness-matching paradigms. In addition, the loudness growth of sinusoids was observed at frequencies associated with individual minima or maxima in the hearing threshold from five subjects using a loudness-matching paradigm. At low levels, loudness growth depended on the position of the test- or reference-tone frequency within the threshold fine structure. The slope of loudness growth differs by 0.2 dB/dB when an identical test tone is compared with two different reference tones, i.e., a difference in loudness growth of 2 dB per 10-dB change in stimulus. Finally, loudness growth was measured for the same five subjects using categorical loudness scaling as a direct-scaling technique with no reference tone instead of the loudness-matching procedures. Overall, an influence of hearing-threshold fine structure on loudness perception of sinusoids was observable for stimulus levels up to 40 dB SPL--independent of the procedure used. Possible implications of fine structure for loudness measurements and other psychoacoustic experiments, such as different compression within threshold minima and maxima, are discussed.     

Comparison of direct and indirect calculations of laryngeal airway resistance in connected speech

Direct measures of subglottal pressure obtained through a tracheal puncture were used to calculate laryngeal airway resistance. Six subjects completed tasks including syllable trains and more natural speech samples produced at three loudness levels. Direct calculations of natural speech resistance values were compared with indirect estimates obtained during syllable train production. The degree of correspondence between direct and indirect calculations varied by subject. Overall, the smallest relative errors among calculations occurred for syllable trains, with higher relative errors for the monologue and sentence. For loudness conditions, the smallest and largest relative errors occurred for soft and loud productions, respectively. The clinical utility of indirect estimation is questioned and suggestions for improving its validity are provided.     

Loudness reduction and adaptation induced by a contralateral tone

An intermittent tone in one ear may induce a large decline in the loudness of a continuous tone in the contralateral ear [Botte et al., J. Acoust. Soc. Am. 72, 727-739 (1982)]. To uncover the basis for this induced loudness adaptation, the method of successive magnitude estimations was used to measure the loudness of a test tone in one ear during and after a single presentation of a brief inducer tone in the contralateral ear. Duration and frequency of the inducer were varied. The frequency of the test tone was set at 500, 1000, or 3000 Hz. Both inducer and test tones were at 60 dB SPL. When the inducer lasted 5 s or more and was at the same frequency as the test tone, the loudness of the test tone was reduced by 80% to 100% while the inducer was on. As the inducer frequency moved away from the test tone, the loudness reduction declined gradually except for a more marked drop at the point where the frequency separation exceeded the critical bandwidth. Loudness remained depressed after the inducer went off. Additional measurements showed that the amount of loudness reduction corresponded closely to the measured movement of the inducer's sound image away from the center of the listener's head (decentralization).     

Differences in loudness of positive and negative Schroeder-phase tone complexes as a function of the fundamental frequency

Tone complexes with positive (m+) and negative (m-) Schroeder phase show large differences in masking efficiency. This study investigated whether the different phase characteristics also affect loudness. Loudness matches between m+ and m- complexes were measured as a function of (1) the fundamental frequency (f0) for different frequency bands in normal-hearing and hearing-impaired subjects, and (2) intensity level in normal-hearing subjects. In normal-hearing subjects, the level of the m+ stimulus was up to 10 dB higher than that of the corresponding m- stimulus at the point of equal loudness. The largest differences in loudness were found for levels between 20 and 60 dB SL. In hearing-impaired listeners, the difference was reduced, indicating the relevance of active cochlear mechanisms. Loudness matches of m+ and m- stimuli to a common noise reference (experiment 3) showed differences as a function of f0 that were in line with direct comparisons from experiment 1 and indicated additionally that the effect is mainly due to the specific internal processing of m+. The findings are roughly consistent with studies pertaining to masking efficiency and can probably not be explained by current loudness models, supporting the need for incorporating more realistic cochlea simulations in future loudness models.     

Frequency selectivity in loudness adaptation and auditory fatigue

An intermittent monaural tone may induce a decline in the loudness of a continuous tone presented to the same ear [Canévet et al., Br. J. Audiol. 17, 49-57 (1983)]. Two experiments studied the frequency selectivity of loudness adaptation induced in this manner. The method of successive magnitude estimations was used to measure the loudness of a monaural 84-s test tone before and after a single presentation of a 24-s inducer tone in the same ear. The first experiment shows that, for an inducing tone (500, 1000, or 3000 Hz) approximately 15 dB more intense than a test tone set to one of 21 different frequencies, adaptation is greatest when the two tones have the same frequency; with increasing difference between the test-tone and inducer frequencies, adaptation progressively declines. The second experiment measured frequency selectivity in the loudness reduction caused by a 1000-Hz inducer as a function of its level. As inducer level went from 75 to 95 dB (with test tone constant at 60 phons), selectivity passes progressively from the type seen in short-term or low-level fatigue (maximal for the 1000-Hz test tone) to a type seen in long-term or high-level fatigue (maximal for the 1000-Hz test tone) to a type seen in long-term or high-level fatigue (maximal at frequencies higher than that of the inducer or fatiguing tone). A common cochlear origin and a continuity between the mechanisms of ipsilaterally induced adaptation and high-level fatigue are suggested by the data.     

Relation between annoyance and single-number quantities for rating heavy-weight floor impact sound insulation in wooden houses

This study investigated the relation between annoyance and single-number quantities to rate heavy-weight floor impact sound insulation. Laboratory experiments were conducted to evaluate the subjective response of annoyance resulting from heavy-weight floor impact sounds recorded in wooden houses. Stimuli had two typical spectra and their modified versions, which simulate the precise change in frequency response resulting from insulation treatments. Results of the first experiment showed that the Zwicker's percentile loudness (N(5)) was the quantity to rate most well annoyance of heavy-weight impact sound over a wide sound level range. The second experiment revealed that arithmetic average (L(iFavg,Fmax)) of octave-band sound pressure levels measured using the time constant "fast" and Zwicker's percentile loudness (N(5)) much better described annoyance by the precise change in the sound spectrum attributable to insulation treatments than Japanese standardized single-number quantities (L(i,Fmax,r), L(iA,Fmax), and L(i,Fmax,Aw)) do. Japanese standardized single-number quantities using the A-weighting curve as a rating curve were found to be excessively influenced by the 63 Hz octave-band sound level and have the great sound level-dependences in the relation with subjective ratings.     

Constancy of loudness of pipe organ sounds at different locations in an auditorium

Pipe organ sounds, as judged by ear, tend to remain constant across different locations in an auditorium, yet the SPL of line spectra may vary by a maximum of 26 dB (mean 8.98 dB, s.d. 2.5), and the overall level may vary, typically, 10 to 12 dB from location to location. However, organs are designed, listened to, and regulated using the psychophysical units of loudness and timbre, and it is possible that the heard sound constancy exists at the psychophysical level. The present work recorded the sound of the C's and G's of pipe organ stops at three different locations in a church. The sound pressure levels were transformed to loudness. Similarity of loudness across the locations was measured two ways. First, the bass to treble distribution of loudness across the compass was measured using cross-correlation functions across pairs of locations. Second, the degree of similarity of loudness at the different locations was quantified by calculating ratios of loudness between the different locations. By these measures, the bass to treble loudness distribution and absolute loudness of the reeds were found to be nearly identical at the three locations. Two psychophysical processes were shown to be responsible for the loudness constancy. The first depended upon the power summation of harmonics within each third octave band above band 9 which contain two or more harmonics. The power summation of these harmonics greatly reduced the effect of SPL variability of the line spectra contained within these higher numbered bands. The second depended upon interharmonic loudness summation and upward masking of the first six harmonics. Greater loudness variability at the different locations was found after transforming the SPL measurements of two 8-ft diapasons to loudness compared with the reeds. The larger loudness variability was due to the smaller number of harmonics above the third of the diapasons compared with the reeds. The psychoacoustic measures indicate what a listener will hear as he/she moves among the locations.     

Three-dimensional vocal tract imaging and formant structure: varying vocal register, pitch, and loudness

Although advances in techniques for image acquisition and analysis have facilitated the direct measurement of three-dimensional vocal tract air space shapes associated with specific speech phonemes, little information is available with regard to changes in three-dimensional (3-D) vocal tract shape as a function of vocal register, pitch, and loudness. In this study, 3-D images of the vocal tract during falsetto and chest register phonations at various pitch and loudness conditions were obtained using electron beam computed tomography (EBCT). Detailed measurements and differences in vocal tract configuration and formant characteristics derived from the eight measured vocal tract shapes are reported.     

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. As reported often in previous loudness-matching studies, loudness summation depended strongly on level. With increasing SPL, the level difference between the noises needed to keep them equally loud first increased, to around 10 dB at moderate levels, and then decreased. Except for one listener, the RT data show the same pattern. The level difference needed to keep RT to the two noises the same first increased and then decreased. These results show that RT is closely related to loudness, but not to sensation level. If RT depended on sensation level, the level difference between the two noises needed to achieve equal RT would not change with SPL because the difference in sensation level between two sounds is a constant. Overall, the average results provide strong support for the contention that simple RT and loudness are closely related.     

关于音乐厅响度评价的研究

该文回顾并综述了对音乐厅(包括西洋交响乐厅及中国民族音乐厅)响度评价的研究历程,指出采用乐队齐奏强音标志乐段的平均声压级L_pF作为评价音乐厅响度客观指标的合理性与可行性。文中给出L_pF的计算方法以及对若干厅堂计算值与实测值的比较,并通过主观评价,给出L_pF的初步优选值域。采用L_pF作为响度评价指标的好处不仅在于它能表征听众听到的绝对响度的感受,还在于能预判何种规模的乐队适于在多大规模的音乐厅中演出,以便达到较佳响度效果的问题。     

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. Three psychoacoustic measurements believed to be associated with basilar-membrane motion were investigated: (1) pulsation threshold; (2) loudness functions derived from temporal integration; and (3) loudness functions derived from loudness matches between pure tones and multitone complexes. Results of the psychoacoustic measurements and of the tone-burst otoacoustic emissions led to very similar estimations of basilar-membrane motion. Accordingly, emissions could serve as an excellent tool--one that is objective, noninvasive, and rapid--for estimating relative basilar-membrane motion.     

复杂谐波信号中响度和谱质心的相互影响——响度和谱质心辨别阈的实验研究

根据阈值测量实验和变化一致性测量实验,在单自变量干扰和双自变量干扰两种情况下量化分析响度和谱质心之间的交互关系。研究发现:(1)复杂谐波信号中谱质心对响度的影响强于响度对谱质心的影响;(2)声音的变化方向对被试判断响度和谱质心的阈值存在影响。研究结果进一步呈现了响度和谱质心的定量特征,为听觉属性交互关系的深入研究提供了新的思路。      

Spectral loudness summation of nonsimultaneous tone pulses

The level of broadband signals is usually lower than that of equally loud narrow-band signals. This effect, referred to as spectral loudness summation, is commonly measured for broadband signals where all frequency components are presented simultaneously. The present study investigated to what extent spectral loudness summation also occurs for nonsimultaneously presented frequency components. Spectral loudness summation was measured in normal-hearing listeners with an adaptive forced-choice procedure for sequences of short tone pulses with varying frequencies, randomly chosen from a set of five frequencies. In addition, spectral loudness summation was measured for the simultaneous presentation of all five frequencies. The comparison stimulus consisted of tone pulses with the same frequency for all tone pulses of the sequence and the same repetition rate and overall duration as the test signal. The pulse duration was 10, 20, 50, or 100 ms and the inter-pulse interval ranged from 0 to 390 ms. In general, a considerable nonsimultaneous spectral loudness summation was found for short pulse durations and inter-pulse intervals, but a residual effect was also observed for the largest inter-pulse interval. The data are discussed in the light of repetition-rate dependent spectral loudness summation and effects of persistence of specific loudness after tone-pulse offset.     

Verification of two minimally invasive methods for the estimation of the contact pressure in human vocal folds during phonation

The contact pressure on the vocal fold surface during high pitch or amplitude voice production is believed to be one major source of phonotrauma. Models for the quantitative estimate of the contact pressure may be valuable for prevention and treatment. Various indirect and minimally invasive approaches have been purported to estimate contact pressure. But the accuracy of these methods has not yet been objectively verified in controlled laboratory settings. In the present study, two indirect approaches for the estimation of the contact pressure were investigated. One is based on a Hertzian impact model, and the other on a finite element model. A probe microphone was used for direct measurements of the contact pressure and verifications of the indirect approaches. A silicone replica of human vocal folds was used as a test bed. Consistent contact pressure estimations were obtained using all three methods. The advantages and disadvantages of each approach for eventual clinical applications are described.     

Examining the use of a time-varying loudness algorithm for quantifying characteristics of nonlinearly propagated noise (L)

A previous letter by Gee et al. [J. Acoust. Soc. Am. 121, EL1-EL7 (2007)] revealed likely shortcomings in using common, stationary (long-term) spectrum-based measures to quantify the perception of nonlinearly propagated noise. Here, the Glasberg and Moore [J. Audio Eng. Soc. 50, 331-342 (2002)] algorithm for time-varying loudness is investigated. Their short-term loudness, when applied to a shock-containing broadband signal and a phase-randomized signal with equivalent long-term spectrum, does not show a significant difference in loudness between the signals. Further analysis and discussion focus on the possible utility of the instantaneous loudness and the need for additional investigation in this area.     

An effect of temporal asymmetry on loudness

A set of experiments was conducted to examine the loudness of sounds with temporally asymmetric amplitude envelopes. Envelopes were generated with fast-attack/slow-decay characteristics to produce F-S (or "fast-slow") stimuli, while temporally reversed versions of these same envelopes produced corresponding S-F ("slow-fast") stimuli. For sinusoidal (330-6000 Hz) and broadband noise carriers, S-F stimuli were louder than F-S stimuli of equal energy. The magnitude of this effect was sensitive to stimulus order, with the largest differences between F-S and S-F loudness occurring after exposure to a preceding F-S stimulus. These results are not compatible with automatic gain control, power-spectrum models of loudness, or predictions obtained using the auditory image model [Patterson et al., J. Acoust. Soc. Am. 98, 1890-1894 (1995)]. Rather, they are comparable to phenomena of perceptual constancy, and may be related to the parsing of auditory input into direct and reverberant sound.     

Time course of loudness recalibration: implications for loudness enhancement

Loudness recalibration, the effect of a relatively loud 2500-Hz recalibrating tone on the loudness of a relatively soft 2500-Hz target tone, was measured as a function of the interstimulus interval (ISI) between them. The loudness of the target tone, assessed by a 500-Hz comparison tone, declined when the ISI equaled or exceeded about 200 ms and leveled off at an ISI of about 700 ms. Notably, the target tone's loudness did not change significantly at very short ISIs (< 150 ms). The latter result is incompatible with the literature reporting loudness enhancement in this time window, but is compatible with the suggestion made by Scharf, Buus, and Nieder [J. Acoust. Soc. Am. 112, 807-810 (2002)] that early measurements of enhancement were contaminated by the influence of the recalibrating tone on the comparison tone when the two shared the same frequency. In a second experiment the frequency of the comparison tone was changed to 2500 Hz and the results of a loudness enhancement paradigm was successfully predicted from the time course of recalibration obtained in experiment 1.     

Spectral loudness summation as a function of duration

Loudness was measured as a function of signal bandwidth for 10-, 100-, and 1000-ms-long signals. The test and reference signals were bandpass-filtered noise spectrally centered at 2 kHz. The bandwidth of the test signal was varied from 200 to 6400 Hz. The reference signal had a bandwidth of 3200 Hz. The reference levels were 45, 55, and 65 dB SPL. The level to produce equal loudness was measured with an adaptive, two-interval, two-alternative forced-choice procedure. A loudness matching procedure was used, where the tracks for all signal pairs to be compared were interleaved. Mean results for nine normal-hearing subjects showed that the magnitude of spectral loudness summation depends on signal duration. For all reference levels, a 6- to 8-dB larger level difference between equally loud signals with the smallest (delta f = 200 Hz) and largest (delta f = 6400 Hz) bandwidth is found for 10-ms-long signals than for the 1000-ms-long signals. The duration effect slightly decreases with increasing reference loudness. As a consequence, loudness models should include a duration-dependent compression stage. Alternatively, if a fixed loudness ratio between signals of different duration is assumed, this loudness ratio should depend on the signal spectrum.     

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. The present results corroborate existing data for 200-ms tones in normal listeners and provide new data for 5-ms tones. On average, the binaural level difference required for equal loudness of monaural and binaural tones is about the same for 5- and 200-ms tones of equal level and changes as a function of level. The group data for normal and impaired listeners are in reasonable agreement with data in the literature. However, the data from some of the impaired listeners deviate markedly from the average, indicating that group data do not accurately represent the behavior of all impaired listeners. Derived loudness functions from the loudness-matching data are reasonably consistent with individual data in the literature.     

The influence of middle-ear muscle contraction on auditory threshold for selected pure tones

The influence of middle-ear muscle (MEM) contraction on auditory threshold has been measured for pure tones of 0.25, 0.5, and 1.5 kHz. The reflex-activating signal was a 3-kHz pure tone. Signal paradigms were chosen to reduce or eliminate the effects of binaural loudness summation, contralateral direct masking, and contralateral remote and backward masking effects, and to maximize the influence of MEM contraction. Results indicate that under no condition was behavioral threshold affected by the MEM contraction induced using a pure-tone stimulus of 3 kHz, 105 dB SPL.