摘要:

First‐order intermodulation components in cochlear‐microphonic potentials were measured with the differential electrode technique from all four turns of the guinea pig cochlea. Measurements were made with six pairs of primary frequencies and a wide range of primary signal intensities. The spatial patterns of the first‐order difference tones were compared with those of the primaries, and with pure tones whose frequency was the same as that of the difference tone. The results indicated that at low and moderate primary intensity levels the distortion component was localized in the cochlea somewhat apical from the region of maximum excitation by the higher‐frequency primary. With increasing stimulus intensity, a general shift of the distribution pattern was observed, accompanied by the development of a second region of maximal difference‐tone activity. This second region, where the difference tone became more prominent as the intensity was increased, corresponded to the location of maximal microphonic elicited by a pure tone whose frequency was the same as that of the difference tone. These results further confirm that distortion of the cochlear microphonic is a two‐stage process.

ISSN:0001-4966    

DOI:10.1121/1.1912587

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

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.

ISSN:0001-4966    

DOI:10.1121/1.1912588

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

In order to determine if speech spectrograms can be used to identify human beings, two questions must be studied: (1) does the formant structure of phonemes uttered by a certain speaker change over a long interval of time, and (2) can the formant structure be changed by disguise, or is it even possible to imitate the formant structure of another speaker? Spectrograms of utterances produced by seven speakers and recorded over periods of up to 29 years showed that the frequency position of formants and pitch of voiced sounds shift to lower frequencies with increasing age of test persons. Speech spectrograms of texts spoken in a normal and a disguised voice revealed strong variations in formant structure. Speech spectrograms of utterances of well‐known people have been compared with those of imitators. The imitators succeeded in varying the formant structure and fundamental frequency of their voices, but they were not able to adapt these parameters to match or even be similar to those of imitated persons.

ISSN:0001-4966    

DOI:10.1121/1.1912589

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

A noise whose amplitude envelope followed closely that of a concomitant speech signal was generated by multiplying white noise and the amplitude envelope of the speech, permitting the signal‐to‐noise (S/N) ratio to be specified on a short‐time nonvarying basis. The spectrum of the amplitude envelope for continuous speech was studied, and the distributions of the vowel and consonant levels in articulation test materials were determined. Articulation functions in such noise and in continuous white noise were generated. Within the range of S/N ratios studied, the gains of the functions for vowels and consonants were 4% and 2.5% per decibel, respectively, in both types of noises. The results clearly depict the operational differences between conventional and envelope‐noise S/N‐ratio specification and suggest that use of the envelope‐noise masker may eliminate some of the problems associated with current methods.

ISSN:0001-4966    

DOI:10.1121/1.1912590

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Echograms of the dorsal surface of the tongue in the midsagittal plane and in coronal oblique planes are presented. Comparisons are made among tongue height measurements obtained from the transverse and longitudinal echograms and from lateral head x rays. It is concluded that ultrasonic scanning can provide information on the shape of the dorsal surface of the tongue during sustained utterances and in the articulatory rest position.

ISSN:0001-4966    

DOI:10.1121/1.1912591

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Numerical ratings of dissimilarity among 12 American English vowels were analyzed by means of the Shepard‐Kruskal procedure for nonmetric multidimensional scaling. The computer output was a geometric configuration of points representing the vowels whose interpoint distances related (approximately) monotonically to the dissimilarities data—the greater the judged dissimilarity between a pair of vowels, the greater the distance between the associated points. Using a procedure developed by Schönemann and Carroll, the axes from theMD‐SCALanalysis were rotated, translated, and dilated to match a target “configuration” based on certain phonetic features. The dimensions from a three‐dimensional analysis were interpreted as “tongue height,” “tongue advancement,” and “retroflexion” (multipleR= 0.70). When the vowel /ɜ/ was eliminated from the analysis, however, only the first two of these dimensions were needed (multipleR= 0.73).

ISSN:0001-4966    

DOI:10.1121/1.1912592

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

A method is described for determining the shape of the vocal tract from a measurement of the acoustic impulse response at the lips. Under the assumptions that the wave motion is planar and that the losses are negligible, the method gives the area function uniquely. It is further shown that a one‐point measurement cannot provide any information about losses. A preliminary experiment is described which verifies the feasibility of the method.

ISSN:0001-4966    

DOI:10.1121/1.1912593

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

This study investigated binaural sensory processing when continuous nonspeech tonal stimuli were dichotically presented. The experimental task consisted of auditory (frequency) pursuit tracking, and consequently there was no influence of selective attention or competition on the listening task. The target sound was externally controlled, whereas the cursor sound was generated and controlled by the transduced movements of either the subject's tongue or hand. A significant laterality effect was found only when the source of motor control over the acoustic signal was the speech‐related movements of the tongue. The theoretical implications of these results towards a feedback regulatory theory of speech production are discussed.

ISSN:0001-4966    

DOI:10.1121/1.1912594

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

A form of preprocessed speech known to be highly intelligible to normal listeners was heard by a group of hearing‐impaired subjects. The preprocessing technique involves high‐pass filtering (cutoff 1100 Hz, slope 12 dB/oct) and infinite amplitude clipping. The subjects heard both unmodified and filtered/clipped word lists at 40‐, 30‐, and 20‐dB sensation levels. Discrimination scores for 13 out of 17 cases were significantly higher at 20‐ and 30‐dB sensation levels for filtered/clipped speech than for unmodified speech.

ISSN:0001-4966    

DOI:10.1121/1.1912595

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Absolute and frequency‐difference thresholds were determined by the conditioned‐suppression technique. The results show that the average frequency range of audibility at +50 dB sound‐pressure level extends from 86 Hz to 46.5 kHz, with a best frequency near 8 kHz. Individual differences in sensitivity are related to body weight and, probably, age. The average frequency‐difference limen is 3.5% from 125 Hz to 42 kHz. Compared to other mammals, the auditory capacities of guinea pig are within one standard deviation of the mammalian mean on each of six dimensions: high‐frequency and low‐frequency cutoff, lowest intensity, best frequency, area of the audible field, and frequency discrimination.

ISSN:0001-4966    

DOI:10.1121/1.1912596

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP