An adaptive procedure for categorical loudness scaling

In this study, an adaptive procedure for categorical loudness scaling is introduced and evaluated. The procedure adjusts the presentation levels to the subject's individual auditory dynamic range without employing any premeasurement and presents levels in randomized order. The procedure has been named "Oldenburg-ACALOS" (Oldenburg-Adaptive CAtegorical LOudness Scaling). It was evaluated using repeated measurements with ten subjects with normal hearing and ten subjects with sensorineural hearing impairment. The results of this investigation revealed that the adaptive procedure provides greater reliability, while being more time efficient than a reference procedure that uses constant stimuli.     

Loudness of brief tones measured by magnitude estimation and loudness matching

McFadden [J. Acoust. Soc. Am. 57, 702-704 (1975)] questioned the accuracy and reliability of magnitude estimation for measuring loudness of tones that vary both in duration and level, whereas Stevens and Hall [Percept. Psychophys. 1, 319-327 (1966)] reported reasonable group data. To gain insight into this discrepancy, the present study compares loudness measures for 5- and 200-ms tones using magnitude estimation and equal-loudness matches from the same listeners. Results indicate that both procedures provide rapid and accurate assessments of group loudness functions for brief tones, but may not be reliable enough to reveal specific characteristics of loudness in individual listeners.     

Temporal integration of loudness in listeners with hearing losses of primarily cochlear origin.

To investigate how hearing loss of primarily cochlear origin affects the loudness of brief tones, loudness matches between 5- and 200-ms tones were obtained as a function of level for 15 listeners with cochlear impairments and for seven age-matched controls. Three frequencies, usually 0.5, 1, and 4 kHz, were tested in each listener using a two-interval, two--alternative forced--choice (2I, 2AFC) paradigm with a roving-level, up-down adaptive procedure. Results for the normal listeners generally were consistent with published data [e.g., Florentine et al., J. Acoust Soc. Am. 99, 1633-1644 (1996)]. The amount of temporal integration--defined as the level difference between equally loud short and long tones--varied nonmonotonically with level and was largest at moderate levels. No consistent effect of frequency was apparent. The impaired listeners varied widely, but most showed a clear effect of level on the amount of temporal integration. Overall, their results appear consistent with expectations based on knowledge of the general properties of their loudness-growth functions and the equal-loudness-ratio hypothesis, which states that the loudness ratio between equal-SPL long and brief tones is the same at all SPLs. The impaired listeners' amounts of temporal integration at high SPLs often were larger than normal, although it was reduced near threshold. When evaluated at equal SLs, the amount of temporal integration well above threshold usually was in the low end of the normal range. Two listeners with abrupt high-frequency hearing losses (slopes > 50 dB/octave) showed larger-than-normal maximal amounts of temporal integration (40 to 50 dB). This finding is consistent with the shallow loudness functions predicted by our excitation-pattern model for impaired listeners [Florentine et al., in Modeling Sensorineural Hearing Loss, edited by W. Jesteadt (Erlbaum, Mahwah, NJ, 1997), pp. 187-198]. Loudness functions derived from impaired listeners' temporal-integration functions indicate that restoration of loudness in listeners with cochlear hearing loss usually will require the same gain whether the sound is short or long.     

Noncombination of pitch and loudness in multidimensional scaling

Carvellas and Schneider [J. Acoust. Soc. Am 51, 1839--1848 (1972)], using magnitude estimates of the dissimilarity of sinusoidal tones in a multidimensional scaling program, found that their data fit a city-block and a Euclidean metric equally well, but other research has indicated that subjects do not combine dimensions of sinusoidal tones to arrive at an overall estimate of stimulus similarity. Yet multidimensional scaling seems to require subjects to combine dimensions of similarity. In this leter a model is put forward to demonstrate that subjects need not combine dimensions directly in order to generate dissimilarity judgments that are very close to either the city-block or Euclidean metrics. Thus it is possible that while subjects do not combine the dimensions perceptually they can adopt a cognitive strategy that leads one to believe they do.     

Temporal integration of tone glides

Temporal integration of rising and falling tone glides against a 50-2800-Hz background of noise at a sound pressure level of 60 dB re 20 micronPa was studied in two experiments. Glides were in the frequency ranges 200-700 Hz and 1200-1700 Hz for durations of 5-120 ms. Results indicate an asymmetry in the detectability of rising and falling glides of short duration, with rising glides detected at lower signal intensities in both frequency ranges. These effects are discussed in terms of differences in pattern of frequency analysis of identical, but temporally reversed, waveforms.     

Temporal scaling at Feigenbaum points and nonextensive thermodynamics

We show that recent claims for the nonstationary behavior of the logistic map at the Feigenbaum point based on nonextensive thermodynamics are either incorrect or can be easily deduced from well-known properties of the Feigenbaum attractor. In particular, there is no generalized Pesin identity for this system, the existing attempts at proofs being based on misconceptions about basic notions of ergodic theory. In deriving several new scaling laws of the Feigenbaum attractor, thorough use is made of its detailed structure, but there is no obvious connection to nonextensive thermodynamics.     

The effect of loudness on the reverberance of music: reverberance prediction using loudness models

This study examines the auditory attribute that describes the perceived amount of reverberation, known as "reverberance." Listening experiments were performed using two signals commonly heard in auditoria: excerpts of orchestral music and western classical singing. Listeners adjusted the decay rate of room impulse responses prior to convolution with these signals, so as to match the reverberance of each stimulus to that of a reference stimulus. The analysis examines the hypothesis that reverberance is related to the loudness decay rate of the underlying room impulse response. This hypothesis is tested using computational models of time varying or dynamic loudness, from which parameters analogous to conventional reverberation parameters (early decay time and reverberation time) are derived. The results show that listening level significantly affects reverberance, and that the loudness-based parameters outperform related conventional parameters. Results support the proposed relationship between reverberance and the computationally predicted loudness decay function of sound in rooms.     

The measurement of loudness in individual children and adults by absolute magnitude estimation and cross-modality matching

Twelve adults and 11 children (age range 4-7 years) performed absolute magnitude estimation of the apparent lengths of lines and the loudnesses of 1000-Hz tones as well as cross-modality matching between loudness and apparent line length. Consistent with the notion that children and adults have similar impressions of loudness, there were no major differences between the absolute magnitude estimation (AME) and cross-modality matching (CMM) data of the adults and children. A direct comparison between the exponents for loudness by AME and CMM was made when a correction factor was employed to eliminate the effects of idiosyncratic use of numbers from the AME exponents. The results support the hypothesis that, with proper instructions, both children and adults can judge stimuli on an absolute scale. Specifically, for 9 out of 12 adults and 9 out of 11 children, lines and tones assigned the same number in absolute magnitude estimation were judged to be subjectively equal in cross-modality matching.     

A new pixel matching method using the entire modulation of the measured object in online PMP

A method using entire modulation information of the measured object itself for pixel matching is proposed in online phase measuring profilometry (PMP). Only one fixed sinusoidal grating is projected onto the moving measured object and then five deformed patterns are captured by the imaging system (CCD). Because the contrast of the sinusoidal grating is a constant, the modulation distribution of each deformed pattern reflecting the gray of the measured region can be extracted. The entire modulation of the object cut from one of them is regarded as a template, and then the distance of the measured object's movement between each two adjacent deformed pattern can be calculated by the correlation operation so that we can cut the corresponding parts containing the measured object's information from five deformed patterns. Then the discrete phase can be calculated with Stoilov algorithm. By the phase unwrapping and the mapping algorithm, the object can be reconstructed exactly. A series of simulations and experiments confirm its feasibility and validity.     

纯音信号的响度与响度差阈的关系

关于响度与响度差阈关系的己有假设总是不能很好地解释心理声学的实验结果,这些假设也不曾对响度的编码和判断的物理过程以及物理过程与心理反映间的联系作过明确的描述。本文基于信号检测理论和关于响度编码的两个假设:响度是一定时间T内的听神经电冲动的记数、稳态纯音激励的神经电冲动速率的时间分布是一个平稳的正态随机分布,得出纯音信号的响度差阈与响度的比与强度无关。这一关系很好地解释了纯音信号强度差阈测试的实验结果,尤其是以前难以解释的Weber比的中部突起、near miss to Weber's law。     

Temporal integration in the presence of off-frequency maskers

Temporal integration was measured at a relatively low and a relatively high signal frequency under conditions of off-frequency masking. The masker was typically gated for 300 ms, and the signal was presented 70 ms after masker onset. In experiment 1, the signal frequency was 500 or 2000 Hz. Temporal integration was measured in quiet and in the presence of a masker whose frequency was lower or higher than the signal frequency. In all listening situations, there was less integration at 2000 Hz than at 500 Hz. This effect of frequency was particularly dramatic in the presence of a lower frequency masker, where there was almost no integration at 2000 Hz. Experiment 2 showed that this dramatic effect of frequency cannot be understood in terms of the underlying psychometric functions. Experiment 3 measured temporal integration at 750 and 2000 Hz for a large number of masker-signal frequency separations for both a tonal and a noise masker, and in conditions where the masker was gated or continuous. The results with the gated tonal masker largely confirmed the results of experiment 1. The results with the continuous tonal masker and the gated or continuous noise masker, however, were quite different. In those cases, the amount of temporal integration at both signal frequencies was more or less independent of the masker-signal separation; the masked temporal integration was nearly equal to the integration in quiet. Thus based on the conditions evaluated here, off-frequency masked temporal integration differs substantially from integration in quiet only for gated tonal maskers located considerably lower in frequency than the signal. It is unclear how to account for this finding, although it may be related to attentional factors.     

Prediction of absolute thresholds and equal-loudness contours using a modified loudness model

The loudness model described by Moore et al. [J. Audio Eng. Soc. 45, 224-240 (1997)] forms the basis for a recent ANSI standard for the calculation of the loudness of steady sounds. However, the model does not give accurate predictions of the absolute thresholds published in a recent ISO standard. Here it is described how the assumed middle-ear transfer function in the model can be modified to give more accurate absolute threshold predictions. The modified model also gives reasonably accurate predictions of the equal-loudness contours published in a recent ISO standard.     

Temporal integration of the contralateral acoustic-reflex threshold and its age-related changes

Although numerous studies have investigated temporal integration of the acoustic-reflex threshold (ART), research is lacking on the effect of age on temporal integration of the ART. Therefore the effect of age on temporal integration of the ART was investigated for a broad-band noise (BBN) activator. Subjects consisted of two groups of adults with normal-hearing sensitivity: one group of 20 young adults (ten males and ten females, ages 18-29 years, with a mean age of 24 years) and one group of 20 older adults (ten males and ten females, ages 59-75 years, with a mean age of 67.5 years). Activating stimulus durations were 12, 25, 50, 100, 200, 300, 500, and 1000 ms. Significant main effects for duration and age were obtained. That is, as the duration increased, the acoustic reflex threshold for BBN decreased. The interactions of duration x age group and duration x hearing level were not significant. The result of pair-wise analysis indicated statistically significant differences between the two age groups at durations of 20 ms and longer. The observed age effect on temporal integration of the ART for the BBN activator is interpreted in relation to senescent changes in the auditory system.     

Temporal integration and compression near absolute threshold in normal and impaired ears

The decrease in absolute threshold with increasing stimulus duration (often referred to as "temporal integration") is greater for listeners with normal hearing than for listeners with sensorineural hearing loss. It has been suggested that the difference is related to reduced basilar-membrane (BM) compression in the impaired group. The present experiment tested this hypothesis by comparing temporal integration and BM compression in normal and impaired ears at low levels. Absolute thresholds were measured for 4, 24, and 44 ms pure-tone signals, with frequencies (f(s)) of 2 and 4 kHz. The difference between the absolute thresholds for the 4 and 24 ms signals was used as a measure of temporal integration. Compression near threshold was estimated by measuring the level of a 100 ms off-frequency (0.45f(s)) pure-tone forward masker required to mask a 44 ms pure-tone signal presented at sensation levels of 5 and 10 dB. There was a significant negative correlation between amount of temporal integration and absolute threshold. However, there was no correlation between absolute threshold and compression at low levels; both normal and impaired ears showed a nearly linear response. The results suggest that the differences in integration between normal and impaired ears cannot be explained by differences in BM compression.     

Comparative learning of pitch and loudness identification

This study investigated possible similarities between the ability to identify pitches and the ability to identify loudnesses. Systematic training of musically naive subjects indicated that frequency identification performance improves at about the same rate as intensity identification performance. Examination of frequency and intensity identification behavior of musically trained subjects showed that their ability to code pitch information efficiently does not generalize to an ability to encode loudness information more efficiently than untrained subjects. Intensity identification training curves of musically trained and untrained subjects are similar, but final performance levels are below frequency identification performance levels exhibited by musically trained subjects, especially those with absolute pitch.     

Temporal integration of trains of tone pulses by normal and by cochlearly impaired listeners

Two experiments investigated the temporal integration of trains of tone pulses by normal and by cochlearly impaired listeners. In the first experiment, thresholds were measured for a single 5-ms, 4-kHz tone pulse, and for ten such tone pulses as a function of interpulse interval (delta t). For normal listeners, temporal integration, defined as the threshold difference between one and ten pulses, was about 8 dB for delta t less than 20 ms, and about 5 dB at longer delta t's. For impaired listeners, temporal integration was only about 2-3 dB across the range of delta t's (5-160 ms) studied. A second experiment measured psychometric functions (log d' versus log signal power) for a single pulse and for ten pulses with delta t's of 5 ms and 80 ms. The normal listeners' functions had slopes close to unity in all three conditions, with a few exceptions. The impaired listeners' functions had slopes close to unity for ten pulses with delta t = 5 ms, but had slopes significantly greater than unity for delta t = 80 ms, and for a single pulse. At delta t = 80 ms, the increase in d' relative to the condition with a single tone was similar (a factor of square root of 10) for both impaired and normal listeners, but the threshold difference was smaller for the impaired listeners due to their steeper psychometric functions. For impaired listeners, then, temporal integration at delta t = 80 ms was normal in terms of a change in d' but abnormal when measured as a threshold difference.(ABSTRACT TRUNCATED AT 250 WORDS)     

Temporal integration of acoustic signals by the budgerigar (Melopsittacus undulatus)

Avoidance conditioning and a modified method of limits psychophysical procedure were used to study temporal integration of tone and noise signals in the budgerigar (Melopsittacus undulatus). Integration of both tone and noise signals can be described by a negative exponential function with a time constant of about 200 ms. At very short durations there were differences in the integration of tone and noise signals. These data are similar to those reported for a number of other vertebrates, including man. Thresholds for two complex natural vocalizations of the budgerigar are similar to those of pure tones of equivalent duration.