摘要:

Stereophonic signal presentation was used to assess localization abilities through ear‐level hearing aids. The experiment was performed in a small sound insulated room. Two loudspeakers were 2 m away from the subject forming ±30° azimuths. The subject was sitting on a chair with a head rest. He faced two strings 30 cm apart hanging on the midline between the loudspeakers and lined them up visually. Two additional strings are marked ±15° azimuths. The subject varied the position of a phantom source by controlling the relative level of signal (uninterrupted flow of speech) by means of a potentiometer. Four conditions were tested: unaided, aided with identical gains of the hearing aids and aided with the gains 10 dB different (right or left ear more amplified). Each subject made 10 adjustments for −15, 0, and +15° azimuth. Each subject was tested two times. Seven subjects with normal hearing produced unaided data similar to reported previously [(Theile and Plenge, J. Aud. Eng. Soc.25, 196–200 (1977)]. The results for identical gains were similar to unaided results. The asymmetrical conditions produced images shifted toward the ear getting more amplification. The average shift was +4.6 and −2.6 dB for left and right ear more amplified, respectively. However the amount of shift varied among subjects. The method might have potential for testing localization abilities of hearing‐impaired subjects. [Supported by NIH NISND grant.]

ISSN:0001-4966    

DOI:10.1121/1.2016457

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

The use of signal detection with children provides a precise method for investigating auditory system parameters. This study investigated the use of signal detection with normal hearing children ages 6–12. A yes‐no procedure was designed such that a child could easily learn the task. A trail was initiated by the child pressing a single manipulandum. After initiation of the trial a 1‐sec delay occurred. A “listen” light then occurred simultaneously with a randomly presented (0.50 probability) 1000‐Hz pure tone. Tonal duration was three seconds. The child's task was to release the manipulandum if the tone was perceived. If the tone was not perceived the child was instructed to continue pressing the manipulandum. Tangible reinforcement was automatically dispensed for hits. Using this procedure a dense distribution of latencies were recorded for hits and false alarms. By redefining “yes” responses at 50‐msec intervals different hit and false‐alarm probabilities were obtained. These probabilities were used to construct ROC curves. This method generated a large number of points on the ROC curve with great economy of experimental time. Several stimulus intensities were used to generate functions relating intensity withd′.

ISSN:0001-4966    

DOI:10.1121/1.2016463

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

Two groups of forty subjects each were presented with three minute noise exposures. Test stimuli consisted of four types of interior aircraft noise (two commercial jets, general aviation, helicopter), each presented at levels of 85, 80, 75, and 70 dBA. Subjects were seated in pairs in a transportation system simulator. During the noise exposures one subject group was instructed to converse while the other group was instructed to remain silent. After each noise presentation all subjects rated the annoyance of the noise, judged its acceptability, and estimated how long they could travel in the noise without discomfort. Responses by the speech group were more critical than the reverie group on all three measures. Annoyance ratings and acceptance judgments were approximately 3 dB more severe at low noise levels and approximately 1 dB more severe at high noise levels for the speech group. [Work supported by NASA.]

ISSN:0001-4966    

DOI:10.1121/1.2034848

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

In this laboratory study of annoyance due to traffic noise, the equivalent sound levelLeqwas found to correlate more highly with subject's annoyance measured on a subjective scale than a number of other noise descriptors and subject variables. Although regression analysis showed that a number of other variables was also statistically significant (among them subject's sex, number of truck gear changes, standard deviation of the sound level, and subject's sensitivity to noise), these were not thought to add appreciably to the variance explained byLeqwhen the complexity of considering them in real life is considered. The experiment therefore confirms the use ofLeqas a single, governing variable in determining the annoyance due to traffic noise.

ISSN:0001-4966    

DOI:10.1121/1.2016467

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

TTS from a mild noise condition was measured among three age groups: six young adults, ten 12‐yr and ten 7‐yr old children. All subjects were exposed during 12 min to a broad‐band noise at 96 dB SPL delivered through conventional dynamic earphones. TTS was obtained at 4 kHz in both ears 2, 15, and 30 min following the end of exposure. No difference could be observed between the TTS's from the 12‐yr group and the young adults. The 7‐yr children showed significantly less threshold shift than the older subjects, but on the other hand they appeared to recover more slowly than the latter. The difference obtained between amounts of TTS2were attributed to the poorer hearing sensitivity of the 7‐yr group at the tested frequency, as compared with the 12‐yr or the adult subjects.

ISSN:0001-4966    

DOI:10.1121/1.2016473

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

The ability of observers to discriminate interaural differences in the (modulator) phase or modulation rate of amplitude‐modulated wide‐band noise signals was investigated using a 4AFC paradigm. Among the parameters studied were: modulator waveform; interaural coherency of the noise carriers; and modulation rate. The effect of bandpass filtering after modulation was also investigated. For the case of binaurally incoherent noise, discrimination performance for both phase and modulation rate differences deteriorated rapidly for modulation rates above about 300 Hz. This low‐pass behavior is typical of that found for various monaural phenomena associated with amplitude modulation (e.g., nonspectral pitch) and presumably reflects the ability of auditory systems to utilize information from the envelope of the modulation waveform. For binaurally coherent wide‐band noise, on the other hand, discrimination performance for phase and modulation rate differences were largely independent of (average) modulation rate. [Work supported by NIH.]

ISSN:0001-4966    

DOI:10.1121/1.2016480

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

In a previous study we observed that identification of temporal order in computer‐generated pure‐tone sequences was better than that for tones and glides in sequence [J. E. Kerivan and B. Carey, Percept. Psychophys.20, 489–492 (1976)]. In continuation, the present experiment studied discrimination performance for pure tone sequences and again for tone/glide sequences. Twenty Ss made same/different comparisons of the order of events ranging from 20 to 60 msec. In one condition pure tones at 713, 1031, 1209, and 1514 Hz were used. In another, two unidirectional glissandi chosen from 466–712 Hz, 714–1208 Hz, and their mirror reversals were substituted for 1031 and 1514 Hz. Discrimination performance was significantly better in the tone/glide condition. It was slightly better for the longer event durations. In each pattern, event position No. 4 was the most important cue in the more difficult discriminations. Thus, when same/different discriminations are made on four event pure tone sequences event position, rate, frequency, and temporal continuities should be evaluated.

ISSN:0001-4966    

DOI:10.1121/1.2016484

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

Several aspects of the two‐month‐olds' perception of a phonetic contrast between glides in multisyllabic utterances were explored with the high amplitude sucking paradigm. First, do infants perceive contrasts between glides in the initial (e.g., YADA versus WADA) and medial positions (e.g., DAYA versus DAWA) of multisyllabic utterances? Second, are infants more likely to perceive these contrasts between stressed or unstressed syllables: Our results suggest the following: (1) two‐month olds are sensitive to place‐of‐articulation differences between glides in both the initial and medial positions of multisyllabic utterances; (2) positioning stress on the syllables to be discriminated had little or no effect on the infants' ability to perceive the contrast; and (3) there was no indication that infants were any more sensitive to the contrast in the initial position than in the medial position. Our findings were in complete agreement with those observed previously for infant's perception of stop consonant differences in multisyllabic utterances [Jusczyk and Thompson, Soc. Res. Child Dry. Abstr. (1977)], suggesting that infant's detection of medial contrasts does not depend on the presence of abrupt formant transitions.

ISSN:0001-4966    

DOI:10.1121/1.2016489

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

A series of synthetic, steady‐state vowels varying perceptually from [i] to [I]was used in both identification and discrimination tasks under two conditions. In the control identification condition, each stimulus occurred equally often. Similarly, in the control ABX discrimination condition, each 1‐step ABX trail occurred equally often. in the identification anchor condition, one of the endpoint stimuli occurred more often then the other stimuli. A similar change was made in the ABX anchor condition. In the identification anchor conditions, the category boundary between [i] and [I]shifted toward the more frequently occurring endpoint (anchor), relative to the equiprobable control. The peak ABX discrimination also shifted with anchoring toward the more frequently occurring stimulus (anchor). This change in discrimination performance rules out a response bias interpretation of the anchoring effect in identification. Rather, perceptual factors involving auditory memory or the reevaluation of vowel prototypes may be involved in the anchoring effects and recently reported selective adaptation effects for steady‐state vowels. [Research supported by SUNY Research Foundation and University Funds grants.]

ISSN:0001-4966    

DOI:10.1121/1.2016010

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

The vowels /i/, /a/, and /u/ were synthesized using a Nova minicomputer described earlier [G. Herman, J. Acoust. Soc. Am.61, S68(A) (1977)]. Six normally hearing subjects made similarity judgments of the vowel stimuli which were constructed with the three formant frequencies published earlier for each vowel. The vowels had a rise‐decay time of 20 msec. The formant structures of the vowels varied for four experimental conditions: (1) all three formants present; (2)F1andF2present,F3absent; (3)F1andF3present,F2absent; and (4)F2andF3present,F1absent. Vowel durations of 200 and 300 msec were used for each condition. Twenty‐four experimental conditions resulted and 576 stimulus pairs were used. Subjects listened at MCL and used an equal‐appearing interval scale to make their similarity judgments. Ratings were converted to similarity matrices and submitted to INDSCAL to find perceptual dimensions. Features retrieved related totongue height, tension, andadvancement, withdurationhaving less importance.

ISSN:0001-4966    

DOI:10.1121/1.2016014

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP