摘要:

Short bursts of computer‐generated Gaussian noise were rated by observers for the presence or absence of a 500‐Hz signal tone burst. A multiple regression analysis found for each observer the linear combination of the energies in narrow bands around the tone frequency that best predicts his total ratings. The estimates of the regression coefficients provide graphs of the “frequency responses” of the observers. Most of the reliable variance in the total ratings was accounted for by the regression analysis in terms of energy in narrow bands. Differences among observers are explained in terms of differential weighting by observers of features labeled “tone presence,” “pitch,” and “loudness.”

ISSN:0001-4966    

DOI:10.1121/1.1912577

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

The attenuation characteristics of each of three commercial audiometric headsets of the noise‐barrier type—(1) Aural Research (AR‐100) “Auraldomes,” (2) Madsen (type ME‐70) “Noise‐Excluding Headset,” and (3) Rudmose (RA‐125) “Otocups”—were measured, as were the attenuation characteristics of a standard audiometric headset (Telephonics TDH‐39 earphone with an MX‐41/AR cushion). The threshold‐shift method was used, employing a pure‐tone sound field in an anechoic room. The resulting attenuation data for each of the three noise‐barrier headsets were compared statistically to those for each of the others and to the data for the standard headset. The data were contrasted with those supplied by the manufacturers. In terms of their attenuation capabilities for the octave bands pertinent to audiometry, the Rudmose Otocup (RA‐125) is ranked first, the Auraldome (AR‐100) second, and the Madsen (ME‐70) headset third. It is suggested that attenuation data alone should not determine the acceptability of any such device. The potential user should, in view of the attenuation data yielded by this study, consider such use only after measurement of octave‐band noise levels in the environment in question.

ISSN:0001-4966    

DOI:10.1121/1.1912578

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

The effect of electrical stimulation of the crossed olivocochlear bundle (COCB) on cochlear potentials was studied in anesthetized and immobilized guinea pigs. Sound‐evoked responses and the endocochlear potential were measured simultaneously in the basal turn. The time course and the magnitude of the slow negative potential in the scala media produced by COCB stimulation can be modified by parameters of COCB stimuli. Augmentation of cochlear microphonic and inhibition of whole‐nerve action potential were found to be dependent on the slow negative potential in scala media and on parameters of the acoustic stimulus. The summating potential showed increase of the positivity with COCB stimulation. The role of the positive summating potential on the inhibition of action potential was discussed.

ISSN:0001-4966    

DOI:10.1121/1.1912579

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

The recovery from impulse‐noise induced temporary threshold shift was systematically traced for individual rhesus monkeys and men. In addition to the well‐known logarithmic recovery, three other types of recovery were seen (diphasic, plateau, and rebound). A descriptive model is developed for the classification of these recovery functions. The model postulates the existence of two types of temporary threshold shift, process M and process S, both of which may be seen after impulse‐noise exposure.

ISSN:0001-4966    

DOI:10.1121/1.1912580

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Perception of auditory patterns based on an intensity difference was investigated in 20 experienced normal‐hearing subjects under binaural and monaural listening conditions. Patterns were made up of either three white‐noise bursts or three 1000‐Hz tone bursts which were temporally spaced. Bursts within each pattern differed only in intensity and were either loud (L) or soft (S), i.e., each pattern included one of one intensity and two of the other. The six possible patterns were SLS, LSL, LLS, SSL, LSS, and SLL. The loud bursts remained at a constant intensity and the soft bursts were attenuated by either 9, 7, 5, or 3 dB. Patterns were presented at 50 dB sensation level. Tone‐burst patterns were easier to perceive and resulted in a larger number of correct responses than noise‐burst patterns. However, there was no significant difference between tone‐burst patterns and noise‐burst patterns in the percentage of errors that were pattern reversals. Symmetrical patterns were reversed more frequently than asymmetrical patterns. Auditory pattern reversals are compared to figure‐ground reversal and simultaneous contrast phenomena in vision and are discussed in relation to sensory inhibition.

ISSN:0001-4966    

DOI:10.1121/1.1912581

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

When weak signals are presented in a background of continuous noise, the process of detection and the discrimination of a change in duration appears to be very similar. Two experimental techniques were used to investigate duration discrimination. The procedure in which the difference in duration between signals, ΔT, was varied given a fixed signal‐to‐noise ratio gave different results than the procedure in which signal amplitude was varied given a fixed ΔT. Although there were marked individual differences, all subjects roughly supported the general conclusion.

ISSN:0001-4966    

DOI:10.1121/1.1912582

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

The response bias inYES‐NOdetection with gated noise and simultaneously gated signal plus noise was found to show both sequential and probability contrast. The sequential dependencies showed that the more recent a signal event, the more the response bias shifts away fromYES. Similarly, the more probable the presentation of a signal, the more the response bias shifts away fromYES. The response bias in detection with continuous noise usually shows the opposite effect—response assimilation. The probability of aYESresponse increases with either greater signal probability or with signal recency. It is suggested that the response‐bias learning which has been postulated to occur in detection experiments depends on the stability of the judgmental frame of reference provided by the continuous noise. When this basis is removed, as in the present study, the response pattern parallels that usually observed in signal recognition studies for which responses are assumed to depend on the memory of the previous presentations. It is concluded that the response pattern, assimilation or contrast, depends more on the stability of the frame of reference than on the type of psychophysical task.

ISSN:0001-4966    

DOI:10.1121/1.1912583

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

This paper continues the presentation of data describing detection performance in the monaural detection with contralateral cue (MDCC) situation. Subjects detected a monaural sinusoid burst masked by continuous white noise, either with or without an unmasked contralateral cue. The cue, presented in both intervals of each two‐interval forced‐choice trial, was a sinusoid of the same frequency and duration as the signal, but its phase and intensity were experimentally varied. In three preliminary experiments it was shown that: (1) when the cue nominally matched the signal in phase and intensity, it improved detection for frequencies below about 1200 Hz and was detrimental at frequencies above about 1400 Hz; (2) at 500 Hz, cue phase strongly affected detection performance, some phases resulting in performance much worse than without the cue; (3) at 500 Hz, the effect of cue intensity was small for the cue phase giving best performance (good phase), but increasing the cue intensity was detrimental to performance with a bad phase. With very loud cues, regardless of phase, performance declined with increasing cue intensity. The main experiment was a factorial study to examine the interactions of frequency, cue phase, and cue intensity. Phase was again found to be important at frequencies below about 1200 Hz, and to be more important the louder the cue. Worst performance at midfrequencies was found for the phase representing a cue lead of about 700 μsec. The phase and the related interaural time difference giving best performance were functions of both cue intensity and of cue frequency. No theoretical interpretation is attempted.

ISSN:0001-4966    

DOI:10.1121/1.1912584

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Most comfortable loudness (MCL) levels for pure tones, broad‐ and narrow‐band noise, and connected speech were studied in three independent experiments using Békésy audiometers and young normal‐hearing males and females. Differences in MCL were explored as a function of attenuation rate, sex, frequency of the pure‐tone and narrow‐band stimuli, interrupted versus continuous pure‐tone stimuli, instructional set, session, and a modified Békésy operation which allowed the subject to hold intensity constant over time versus standard Békésy operation. There were no significant sex, set, session, or operation differences. In all three experiments, a 2.5‐dB/sec attenuation rate produced higher MCLs than a 1.25‐dB/sec rate. In general, a 500‐Hz tone or narrow‐band noise centered at 500 Hz was tracked at the highest sound‐pressure levels (SPLs), while broad‐band noise was consistently tracked at the lowest levels. Regardless of frequency or attenuation rate, continuous pure tones were tracked at higher SPLs than interrupted pure‐tone stimuli. Although intersubject variability was relatively high, the majority of test‐retest differences in each experiment was 10 dB or less. Over‐all MCLs in decibels SPLre0.0002 μbar were 49.3 for speech, 49.4 for noise, and 51.7 for pure tones.

ISSN:0001-4966    

DOI:10.1121/1.1912585

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

The signal, a 135‐Hz noise centered at 250 Hz, was partially masked by continuous wide‐band noise. The interaural correlation of both signal and masker was varied between +1.00 and zero. With a correlated masker (N0), detection is about 14 dB better with an uncorrelated signal (SU) than with a correlated signal. The masking‐level difference (MLD) diminishes as the correlation of the signal is increased to unity and as the correlation of the masker is decreased to zero. The results imply that sizable MLDs are obtained under those conditions where the addition of the signal to the noise results in adecreasein the correlation between the stimulus events at the two ears.

ISSN:0001-4966    

DOI:10.1121/1.1912586

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP