Loudness Judgments Research Articles

A common mechanism mediating the time-order error and the cross-over effect in comparative judgments of loudness

Abstract Analysis of data from comparative judgments of loudness suggests that the TOE and the cross-over effect are both reflections of the operation of a common judgment process. This process is tentatively identified as the making of an implicit verbal response which serves to recode the information in the stimuli. The results of three experiments on comparative judgment of loudness are described which are consistent with this suggestion.

Loudness of high-intensity aircraft flyovers

Casual listening to a recorded aircraft flyover at various peak levels up to 111 dBA gave the impression that reducing the level by 10 dB did not seem to reduce the loudness by half. Therefore a group of eight listeners (lab assistants and students experienced in high-intensity noise exposure) were given pairs of flyovers, the first of which was always at 111-dBA peak and called “100” in loudness, and were asked to indicate the loudness of the second, whose peak level ranged from 61 to 106 dBA. Although the loudness-intensity relation was reasonably close to a power function for each individual, the slopes ranged from 6 to 35 dB per halving loudness, with a median of 16 dB. No listener assigned a loudness of “50” or less to a 101-dBA-peak flyover. Thus, if one wishes to halve the loudness of aircraft noise at the ends of runways, it will be necessary to reduce peak levels by considerably more than the 10 dB that represents an extrapolation from loudness judgments made at moderate levels. The same holds, of course, for “noisiness,” and probably also for “annoyingness.” [Research supported by the National Institute for Occupational Safety and Health, Public Health Service.]

Influence of middle-ear muscle contraction on pure-tone suprathreshold loudness judgments.

Some effects of middle−ear muscle (MEM) contraction on TTS and suprathreshold loudness judgments have been assessed in three experiments. Experiment I was designed to demonstrate the effect of MEM contraction on TTS while in Experiments II and III the influence of MEM contraction on the loudness of suprathreshold pure−tone stimuli was measured. In Experiment I, MEM contraction decreased the effective level of a high−intensity TTS−inducing stimulus reaching the cochlea. In Experiments II and III signal paradigms were chosen to reduce or eliminate the effects of binaural loudness summation, and contralateral remote and backward masking effects, and to maximize the influence of MEM contraction. Results of the loudness judgments indicated no effect of binaural interaction, whereas the MEM contraction affected the loudness of pure tones only when the stimuli were low frequencye (250, 500 Hz) and high intensity (≳100 dB SPL). The results further imply that at high intensity levels there was an interaction between the effects of the intensity of the loudness−judgment stimulus and the intensity of the reflex−inducing stimulus. That is, when the reflex was induced the effect on loudness increased as the intensity of the loudness−judgment stimulus was raised; likewise, when the loudness−judgment stimulus was maintained at a constant sound−pressure level but the intensity of the reflex−inducing stimulus was increased, the effect on loudness increased. Subject Classification: 65.50, 65.22, 65.24.

Feedback as a source of information and as a source of noise in absolute judgments of loudness.

Feedback as a source of information and as a source of noise in absolute judgments of loudness.

Feedback as a source of information and as a source of noise in absolute judgments of loudness.

Two experiments investigated the effects of feedback on absolute judgements of loudness. In Experiment 1, subjects received aceurate, unreliable, or no feedback. While feedback improved the information transmitted in judgments, it gave lower d' values than no feedback. These results were not compatible with a signal detection model with a noisy sensory stage and a decision stage with a fixed criterion, but suggested that criteria move in response to feedback and thus contribute judgmental noise to perceptual processes. Further confirmation for a variable criterion was obtained in Experiment 2, where reliability of feedback was held constant, but feedback was biased to favor some response alternatives more than others. Biased feedback shifted the positions of criteria, but also increased the inertia of some criteria in responding to feedback which caused changes in d'.

Individual differences and reliability of information transmission in absolute judgments of loudness, brightness and line lengths.

Information transmission, as estimated from absolute judgments of loudness, brightness and line length, was measured in 35 normal Ss. Each S was tested on all modalities on each of three days. Individuals varied widely in their ability to transmit information and were consistent across modalities and days; reliabilities for loudness, brightness and line length between Days 2 and 3 were 0.72, 0.81, and 0.89 respectively. The mean intercorrelation between modalities was 0.40. WAIS Digit Span but no other intelligence scale was positively correlated with transmission of information. The results suggest the existence of a single information-processing facility in the central nervous system.

Effect of the Contraction of the Middle Ear Muscles on Suprathreshold Loudness Judgments

Changes in the threshold of hearing and suprathreshold loudness judgments have been reported under conditions in which the contraction of the middle ear muscles (MEM) has been induced. These psychophysical changes have been accounted for variously on the bases of contributions of contralateral direct masking, contralateral remote masking (CRM), binaural loudness summation (LS), and the effects of changes in transmission caused by MEM contraction. Experimental conditions were devised to determine the influence of the contraction of the MEM on suprathreshold loudness judgments at 250, 500, and 1500 Hz by controlling the possible influences of CRM and LS. The relative loudness of two sequentially presented 50-msec pulses (identical frequency) was judged by subjects with normal sensitivity (hearing and MEM) using the method of constants during three basic experimental conditions. In Condition A (reference condition), the test stimuli were presented monaurally separated by a 1400-msec interstimulus interval. Condition B was identical to Condition A except that a 1250-msec narrow-band noise (2900–5000 Hz) was presented contralaterally with an onset delayed 200 msec relative to the first test pulse. In Condition C an identical contralateral noise was used but with the onset of the first test pulse simultaneous with the onset of the noise. For each of these three conditions two reference tone intensities (60 and 100 dB SPL) and two narrow-band noise stimulus intensities (70 and 105 dB SPL) were employed. Essentially no suprathreshold loudness changes were observed between the two pulses among the various. conditions. We conclude that MEM contractions did not effect the suprathreshold loudness judgment.

Pure-tone equal-loudness contours for standard tones of different frequencies

Six Ss made judgments of equal loudness by adjusting the intensity of comparison tones of 10 different frequencies. The comparison tones were presented diotically alternately with standaxd tones. Each standard tone remained fixed at one frequency (125, 1,000, or 8,000 Hz) and one intensity (10, 20, 40, or 70 dB sensation level)while collecting the data for any single equal-loudness contour. In this manner, families of equal-loudness contours were generated for each of the three standard frequencies. The contours for the 1,000-Hz standard were compared with those in the literature. The families of contours for the 125- and 8,000-Hz standards, determined by the same algorithm, differed in the spacing of the contours from the 1,000-Hz standard family as well as from each other. Implications for the reflexive, symmetric, and transitive properties of the equal-loudness relation axe discussed.

Loudness Evaluations of the Sound from an Electric Clock

The noise from a consumer electric clock was studied to evaluate loudness estimating procedures. Eight different clock noises were tape recorded for presentation to a panel of people for loudness judgments. An electronic switch enabled the recorded clock noise and a 1000-Hz tone to be presented alternately via earphones for 12-sec durations with 12-sec silences in between signals. The person adjusted the 1000-Hz tone to match the loudness of the clock noise providing a correlation to the phon loudness scale. It was determined that Steven's method generally underestimates the loudness but is usually less than 10 dB in error. If ranking on a relative loudness scale is all that is desired, dB(A) measurements will suffice. [This work was supported by Westclox Division, General Time Corporation, LaSalle, Illinois.]

Hearing: individual differences in perceiving.

Four different types of hearing were investigated using 25 men and 25 women as subjects: pure tone threshold, judgment of loudness, pitch discrimination, and annoyance of a repeating stimulus. Differences were found at high frequency thresholds (above 6000 Hz), in loudness judgment, and in the annoyance test. The pitch discrimination test showed no effect of sex, but a large effect of years of musical training. None of the four hearing parameters investigated bore any statistical relationship to any other, demonstrating that these hearing types are distinct and will vary within, as well as between subjects. Personality assessment showed no relationship to any type of-hearing, with the exception of extraversion and loudness judgment, suggesting that fairly pure sensitivity factors are being measured.

The anchor effects on the judgment of loudness using reaction time as an index of loudness

The present study was designed to investigate anchor effects on loudness judgments, using reaction time (RT) as an index of loudness. In Experiment 1, anchor effects were reexamined using verbal categories. Two kinds of anchor stimuli, 60- and 90-dB SPL 1,000-Hz pure tones, and four kinds of series stimuli, 60-, 70-, 80-, and 90-dB tones, were used. In this experiment, clear anchor effects were found just the same as in our previous experiment. Experiment 2 was conducted using RT as an index of loudness with stimulus conditions similar to those in Experiment 1. The same anchor effects could be seen in this experiment too. As RT is quite free from the limitations inevitably accompanying the verbal responses, it may be concluded that the anchor effects reflect the shift in perception.

Bias-Free Loudness Judgments for White Noise

Loudness judgments are especially sensitive to experimentally induced biases. An earlier study [R. M. Warren, “Elimination of Biases in Loudness Judgments for Tones,” J. Acoust. Soc. Amer. 48, 1397–1403 (1970)] eliminated known biasing factors (by using only single judgments from large groups of unpracticed subjects and employing symmetrical response ranges), and found that half loudness (12L) for tones corresponded to half sound-pressure level (12P) or 6-dB attenuation. The present study extended this procedure to white noise, using 12 separate groups of 30 subjects. It was found that 12L = 12P from about 45 through 90 dB. This relation held for both loudspeaker and diotic headphone stimulation. These results are in agreement with the theory which considers that subjective magnitude estimates for sounds are based upon familiarity of the listener with the relation between level of stimulation and distance from the source. Half L corresponds to the effect of doubling distance and hence corresponds to 12P (or 12 sound energy). It is suggested that the sone scale, which considers 12L = 0.32P (or 10-dB attenuation), reflects the systematic influence of known biasing effects.

Category judgments of loudnesses in the absence of an experimenter-induced identification function: sequential effects and power-function fit.

Category judgments of loudnesses in the absence of an experimenter-induced identification function: sequential effects and power-function fit.

A Laboratory System for Measuring Loudness Loss of Telephone Connections

Transmission performance of the telephone message network has improved steadily over the years. Coincidental with this improvement has been the evolution of rating plans which provide the basis for transmission planning, design, and evaluation. Loudness of telephone speech was an important consideration in this evolution. Telephone speech loudness continues to be one of the major factors which need to be taken into account in telephone transmission engineering. This paper covers a laboratory system, called EARS (Electro-Acoustic Rating System), devised to make objective measurements of partial and overall telephone connections (including electro-acoustic transducer efficiencies) in a manner which reflects subjective loudness loss. Topics covered include a historical review of rating plans, computation of speech loudness, evolution of the EARS, and description of the system and its capabilities. The EARS essentially comprises a sound source and a meter for measuring either acoustical pressure or electrical voltage. Design of the source and meter are based on telephone speech loudness considerations, and measurements made with the system approximate subjective loudness judgments with an accuracy which is sufficient for telephone engineering purposes. The EARS may be used in implementing any telephone transmission rating plan incorporating speech loudness loss as an element. In such application, the system can be used for specifying connection losses, thus eliminating the need for extensive subjective tests of loudness. However, subjective tests will still be required to evaluate effects of other elements, e.g., noise, important in any given plan, and to evaluate the range of loudness losses acceptable for that plan.

Response requirements and the contrast effect in loudness judgments

Ss responded to a series of soft tones via category judgments, reaction time responses, or simple nonquantitative discrimination judgments. An evaluation was then made of the contrast effects obtained in the category judgments of these same soft tones when subsequently presented along with a series of loud tones. A control group was also used which did not receive the initial trials with the soft tones. The results indicated: (1) equivalent contrast effects for all four groups for the soft tones and (2) significantly greater judgments of the loud tones in the group that had used category judgments on the initial trials with soft tones. These results, alonR with a trend analysis, were used to argue for a joint semantic shift and equalization of category usage process underlying the contrast effect when Ss are required to denote the stimuli initially by means of category judgments.

Pure-Tone Equal Loudness Contours for Standard Tones of Different Frequencies

Subjects (14 high-school students) made judgments of equal loudness by adjusting the intensity of comparison tones of ten different frequencies. The comparison tones were presented diotically alternately with standard tones (1-sec duration each). Each standard tone remained fixed at one frequency (125, 1000, or 8000 Hz) and one intensity (10, 20, 40, or 70 dB sensation level) while the data were collected for any single equal loudness contour. In this manner, families of equal loudness contours were generated for each of the three standard frequencies. The contours at 1000 Hz were compared with those for 1000 Hz in the literature. The contours for 125 and 8000 Hz, determined by otherwise using the same algorithm, were different in shape from the 1000-Hz set as well as from each other. These differences implied a violation of the transitivity assumption in the loudness calculating algorithm. Tests for transitivity among the three standard frequencies failed in many cases.

Acoustic level and vocal effort as cues for the loudness of speech.

A review of previous studies of speech loudness shows great variability in the derived psychophysical functions relating loudness to speech power [i.e., sound-pressure level (SPL)] and other physical and psychological measures, such as subglottal pressure (SGP) and vocal effort. This paper argues that, because of the complex nature of speech production and perception, traditional scaling procedures that yield exponential relations between loudness and some other measure should be replaced by multidimensional techniques. Two experiments on speech loudness scaling using partial correlation analysis demonstrate that loudness judgments depend upon both acoustic cues, as measured by peak SPL, and vocal effort cues, as measured by peak SGP in one experiment and subjective effort in the other. The relative dependencies upon these cues are different for different listeners and are at least somewhat resistant to distortion via signal attenuation and/or masking with white noise. These differences between listeners might be exploited in the search for relationships between speaking and listening.

Relative loudness judgments of non-shadowed material presented dichotically.

In a non-shadowing dichotic loudness judgment task, 20 Ss matched speech and white noise intensities at 60, 70, 80, 90, 100, and 110 db. Above 70 db, Ss judged speech to be louder than white noise, at 70 db they were judged to be equally loud, but at 60 db white noise was considered to be louder than speech. These findings are discussed in terms of the attenuability of different types of material.

Analysis of contrast effects in loudness judgments.

Analysis of contrast effects in loudness judgments.

Elimination of Biases in Loudness Judgments for Tones

Loudness judgments are especially sensitive to experimentally induced biases. By using a method derived from studies of visual intensity, it was found possible to obtain loudness estimates free from known biasing factors. Judgments of 50% loudness corresponded to 25% stimulus intensity (6-dB attenuation) for 1000-Hz tones from 42 through 92 dB, and for tones from 250 through 8000 Hz presented at moderate intensity. These results agree with other data supporting the physical correlate theory of sensory intensity. It is suggested that the sone scale of loudness reflects the influence of known experimental biases and hence does not represent a fundamental relation between stimulus and sensation.