摘要:

Design guidelines which incorporate the visual contribution to speech are developed for maximum room size and speaker‐listener distance, and for minimum lighting level on the speaker, when unamplified speech level and background noise level are known. Room‐scale studies on speech intelligibility are conducted at different speech‐to‐noise ratios and different levels of visual acuity. Visual acuity has not been considered as a factor in earlier studies on the visual contribution to speech [W. H. Sumby and I. Pollack, J. Acoust. Soc. Am.26, 212–215 (1954)]. The articulation index is evaluated on the basis of the modified rhyme test in accordance with the newly proposed international standard on speech intelligibility testing. The studies confirm the striking effect of speech‐to‐noise ratio on intelligibility. Also, the contribution of visual cues is shown to be very considerable, especially when the level of audible speech at the receiver is near the background noise level. The amount of improvement in speech intelligibility is shown to depend upon the illumination level on the speaker and the distance from the speaker.

ISSN:0001-4966    

DOI:10.1121/1.2002445

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The beginning of architectural acoustics as an engineering science began with Joseph Henry when he was requested by Congress to design a new lecture hall for the Smithsonian Institution in Washington. Henry's preliminary investigations led him to the discovery of what is now known as the “precedence effect,” setting limits on the permissible time lags in successive acoustic signals before echoing is evident. Henry's design of the lecture hall made skillful use of his discovery for the location and shape of wall and ceiling surfaces to produce much “early reflected sound” to enhance the direct impulses. The next great advance in architectural acoustics was made by Prof. Wallace C. Sabine of Harvard in his quantitative studies of reverberation, and in his masterful use of these discoveries in the acoustical designs for many notable buildings, especially Boston Symphony Hall—still considered one of the world's finest. After Sabine's untimely death in 1919 his work was extended and applied by many others in the next decade, notably, Dayton C. Miller, F. R. Watson, Paul E. Sabine, Carl Eyring, R. F. Norris, and Vern O. Knudsen. The early development and application of architectural acoustics as an exact science was primarily an achievement of the New World, and one of which we can be justly proud in the Bicentennial year.

ISSN:0001-4966    

DOI:10.1121/1.2002452

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The 1920 decade was dominated by new and improved instrumentation and by the Bell Telephone Laboratory program that undertook to measure (physically) speech, hearing, music, noise, and (with E. P. Fowler, Sr.) abnormal hearing. It also introduced syllable articulation and sentence intelligibility tests. Harvey Fletcher summarized all this inSpeech and Hearingin 1929. In 1928 Georg V. Békésy described the traveling wave pattern on the cochlear partition, and in 1930 E. G. Wever and C. W. Bray listened to the electrical output of a cat's auditory nerve. These events initiated a whole new era in the bioacoustics of the ear and the electrophysiology of the auditory system. Psychoacoustic topics of interest included masking, lateralization, combination tones, and subjective scales of pitch and loudness. The different approaches were correlated by S. S. Stevens and H. Davis inHearingin 1938.

ISSN:0001-4966    

DOI:10.1121/1.2002454

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The purpose of this investigation was to determine if listeners were capable of speaker height and weight identification from recorded speech samples of speakers' voices. A standard prose passage was recorded by 30 speakers, 15 females and 15 males. A master tape containing the randomly arranged recorded readings of all speakers was played to a group of 30 subjects. All subjects participated in two experimental sessions. In one session they were asked to determine the height of each speaker and in another session weight judgments were made. The order of presentation of the two experimental tasks was randomized so that 15 subjects made height judgments first and 15 subjects made weight judgments first. A multiple‐choice response sheet containing four choices for height and weight judgments for each speaker was provided. In addition, subjects were also asked to indicate the confidence of their decisions on a seven‐point rating scale, and to describe the criteria upon which they based their decisions. Results indicate that (1) for both order groups, subjects were capable, with better than chance‐guessing accuracy, of correctly identifying the heights and weights of speakers when presented with only recorded speech samples and (2) subjects exhibited slightly greater accuracy in identifying speaker weights than heights, regardless of the order in which they were exposed to the two kinds of identification tasks. Implications of these findings and suggestions for future research are discussed.

ISSN:0001-4966    

DOI:10.1121/1.2002459

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The purpose of this study was to determine the accuracy and reliability of the 3M Viewer in measuring fundamental vocal frequency and to suggest a method of incorporating the 3M Viewer into the clinical measurement of pitch. A total of forty normal speaking persons served as subjects. Recorded sustained terminal vowel segments were obtained from each subject following procedures outlined by Fairbanks and Wilson. The terminal vowel segments were then analyzed utilizing two electronic systems for extracting fundamental frequency (electronic band‐pass filters and digital frequency counter; Kay Elemetrics Sonograph), and 3M Viewer. Measurements made with the 3M Viewer by three observers were submitted to a linear regression analysis. The fundamental vocal frequency estimates from each of the three methods of fundamental frequency determination were submitted to an analysis of variance. Results suggest that the three estimates with the 3M Viewer are not significantly different from one another and that the 3M Viewer method of estimating fundamental vocal frequency is at least as accurate as the other two methods employed in this study.

ISSN:0001-4966    

DOI:10.1121/1.2002463

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

We will conduct an informal open discussion of issues related to stimulus control, choice and design of experiments, theoretical models, and general research strategy in binaural hearing. Topics to be considered include acoustical monitoring of stimuli, variability and drift in subject performance, techniques for determining the shape of binaural images, time‐intensity trading, the relation of lateralization to detection, similarities and differences in current theoretical models, the inadequacy of many previous experiments to critically test and separate models, the incorporation of multiple sampling of inputs into models, and the effects of long‐term previous experience in natural environments on the perception of laboratory stimuli (and the possibility of taking explicit account of such effects in the construction of models. [Work supported by NIH.]

ISSN:0001-4966    

DOI:10.1121/1.2002469

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

It is generally known that subjects' binaurally masked threshold improves when either the signal or noise is presented to the two ears antiphasically. It has similarly been shown that the amplitude of the AER varies as a function of the intensity and presumably therefore loudness of the stimulus. In this study, click stimuli were presented under three conditions: both the stimulus and the masker in phase (SoNo), stimulus in phase and masker antiphasic (soNπ), and the stimulus antiphasic with the masker in phase (SπNo). Subjects' AERs' were obtained at five intensity levels (reSoNo psychophysical threshold). Data are presented demonstrating the amplitude of the AER as a function of stimulus intensity for each of the three signal/noise phase conditions. While differences in the AER amplitudes are detectable for group data, individual responses show considerable variability.

ISSN:0001-4966    

DOI:10.1121/1.2002476

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

CM was recorded from scale media in the first three turns of the guinea pig's cochlea using pure tone acoustic stimulation. Averaging followed by FFT analysis was used to obtain amplitude and phase of the harmonic components. The acoustic stimulus was fixed in frequency at about 120 Hz, and sound pressure level was varied from 0 to 120 dB SPL. As harmonics appeared above the noise level of 0.1 μV, their slope with respect to SPL was found to approximateN× 6 dB/octave, whereNdesignates the number of the harmonic. At about the same SPL, all harmonics demonstrated saturation. At 120 dB SPL roughly 35 harmonics appeared above the noise level. The magnitude data supports a model in which a changing resistance is represented by a real‐valued power function of basilar membrane motion. However, the observed relationships indicate that such a model is inadequate to explain CM generation. [Supported by NIH grant 1P1NS12732‐01.]

ISSN:0001-4966    

DOI:10.1121/1.2002482

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

In the mustache bat (P. p. r.), cochlear microphonic (CM) is sharply tuned at 61 kHz whileN1is tuned at 64 kHz. The amplitude of the CM evoked by a 61‐kHz signal increased and decreased exponentially at the onset and cessation of the stimulus, respectively. Its rise time, which affects the threshold of theN1, varied as a function of the stimulus frequency even for a constant rise time stimulus. The longer the CM rise time, the higher theN1threshold is. To eliminate the effect of the CM rise time on theN1tuning curve, the stimulus rise time was adjusted on the basis of single unit tuning curves and the CM rise time was kept constant. Then theN1tuning curve was measured and was found tuned at 61 kHz instead of 64 kHz. This indicates the difference in best frequency between the CM andN1is simply due to the properties of a sharply tuned resonator andN1, but not due to a mechanism comparable to lateral inhibition. [Work supported by NSF.]

ISSN:0001-4966    

DOI:10.1121/1.2002486

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

There are three principal types of vibration which occur on overhead lines and which are of engineering significance. These are classified as aeolian‐ or vortex‐shedding‐induced, wake‐induced, and the bluff‐body or galloping type of mechanical oscillation. The latter two are self‐excited and are discussed in some detail. Theoretical studies are compared with experimental results and a number of methods of control are described.

ISSN:0001-4966    

DOI:10.1121/1.2002492

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP