摘要:

Long‐time spectral characteristics and distributional properties of speech intensity produced by esophageal speakers were measured and compared with those of normal speakers. Substantial differences were observed in the distributional properties of speech intensity produced by normal and esophageal talkers. On the average, esophageal speech was about 10 dB less intense than normal speech. In addition, the average long‐time spectrum for esophageal speech was characterized by a flattened spectral envelope. Other spectral differences between esophageal and normal speech were found and interpreted in terms of the known variations in voice and speech production of these two divergent forms of oral communication.

ISSN:0001-4966    

DOI:10.1121/1.384306

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

The hypothesis that pairs of appropriate inharmonic sounds can evoke perceptions similar to conventional consonance and dissonance is examined. The inharmonicity considered is not the relatively small displacement of frequency components seen in conventional musical instruments (e.g., piano), but rather large, deliberate shifting of frequencies by a number of semitones. The hypothesis states that if there is a match between upper‐frequency components of two such inharmonic sounds, consonance should be perceived. If near misses occur between upper‐frequency components of the two sounds, causing audible beats, then dissonance should be perceived. The individual inharmonic sounds should have reasonably wide component spacing to avoid a noiselike timbre. This hypothesis was confirmed by experiments in which subjects chose which of two different inharmonic sound pairs was the more consonant. The sound pairs with matching frequency components were chosen more often than those with near misses. The difference was significant for the experimental subjects as a whole and was pronounced for subjects with musical experience. This last fact is important since the sound pairs with matching components were arranged to have conventionally dissonant relationships between their fundamentals, and vice versa for the pairs with near misses. It is speculated that the structures in music which have their origins in the harmonic series (intervals, chords, scales) may be alterable by electronically relocating the harmonics to inharmonic positions.

ISSN:0001-4966    

DOI:10.1121/1.384307

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Mode transitions between the sounding modes of a flute were studied experimentally with an artificial mouth. This consisted of a nitrogen beam blown through a nozzle onto the embouchure of a real flute head pipe connected to a single open pipe. The nature of the transition depends sensitively on the angle of attack, the transverse displacement, and the length of the nitrogen beam. A qualitative model is discussed to understand the nature of the mode transition.

ISSN:0001-4966    

DOI:10.1121/1.384200

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

The intelligibility of the front vowels (/i/, /I/, / /, and /F/) was investigated as sung in four different ways: (1) operatic, (2) in consonant–vowel–consonant (CVC) context, (3) with a raised larynx, and (4) with both raised larynx and in CVC context. All syllables were sung by a trained soprano at F4, A4, C♯5, F5, A5, and C♯6. Ten subjects listened and identified randomized sets of ten tokens of each vowel per condition (method of articulation) at each note. Results showed that, from C♯5(nominal 554 Hz) to F5(698 Hz), the intelligibility of operatic vowels (condition 1) fell from 56% to 16%. The mean intelligibility of the vowels at the three highest notes (F5, A5, C♯6) was 10% for condition 1, 64% for condition 2, 62% for condition 3, and 83% for condition 4. Results indicate that increased intelligibility across conditions is a function of increased energy in the higher harmonics and presence of consonantal transitions. The generally accepted notion that vowel sounds are largely unintelligible on higher notes pertains only to a restricted manner of production.

ISSN:0001-4966    

DOI:10.1121/1.384308

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Catalase and malate dehydrogenase (MDH) were subjected to the sound field produced by a transversely oscillating wire driven at 20 kHz. Catalase was not inactivated under any conditions of sonication whereas MDH inactivation increased exponentially with the duration of sonication and depended upon the initial enzyme concentration. The inactivation was not the result of collapse cavitation or thermal inactivation and was probably related to the presence of acoustic microstreaming.

ISSN:0001-4966    

DOI:10.1121/1.384309

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

To obtain the fine structures of a wave field on a noise emitting object, a new super‐resolution passive imaging system is constructed. The wave field detected by a hemispherically arranged microphone array corresponds directly to the wave field on the object by exploitingaprioriinformation about the object’s physical structures. Thus resolution of one‐tenth of a wavelength is realized. The principle, concrete construction, proposal of proper sound source models, and discussions on the effects of the measuring and additive noises are given, as well as several observed results.

ISSN:0001-4966    

DOI:10.1121/1.384257

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

A low‐frequency transducer in the form of an ’’octagonal ring’’ 10 in. in diameter and 6 in. high, driven by 16 rare earth Terfenol D (Tb0.3Dy0.7Fe2) rods, has been developed. The transducer resonates in a circumferential expansion mode at 775 Hz with a mechanicalQof 2.4. and an effective electromechanical coupling coefficient of 0.4. Results are presented for the transducer operated with and without a polarizing bias up to acoustic output powers of 80 and 350 W, respectively.

ISSN:0001-4966    

DOI:10.1121/1.384258

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Standard reference threshold levels for the Telex 1470‐A audiometric earphones have been determined. The psychoacoustic evaluation of these earphones was completed by loudness balancing at threshold. The earphones were balanced to comparison standard earphones calibrated at the National Bureau of Standards. Coupler calibration was accomplished using the American National Standard Method. Objective (coupler) and subjective (psychoacoustic) data were combined and the resulting reference threshold sound pressure level data are reported herein. These data were compared to previous data for the 1470‐type earphone. While good agreement with previous data was noted for low and mid frequencies, sizeable differences did occur at high frequencies. Possible sources of these discrepancies are discussed.

ISSN:0001-4966    

DOI:10.1121/1.384259

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Reverberation time can be measured from pulse responses by reversed integration of the squared signal. By this method, however, effects of filters cannot be separated from room characteristics. The author has devised a new method by which reverberation responses of rooms only can be obtained. In this method, integrations on time axis are made, not for squared responses, but for complex numbers derived from impulse responses by Fourier transforms.

ISSN:0001-4966    

DOI:10.1121/1.384260

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

The utilization of zero‐crossing (ZC) information to detect signals can provide hardware simplifications and cost reductions compared to conventional linear processing techniques. This paper investigates the effectiveness of a ZC processor that uses ZC statistics to detect a sinusoidal signal in the presence of either sinusoidal interference or Gaussian noise. For the sinusoidal interference case, the frequency distribution of ZC intervals for the sum of two sinusoids with different amplitudes, different frequencies, and a uniformly distributed relative phase was calculated. These results, extending the work of Longuet‐Higgins, Rice, and Blachman, demonstrated that the use of the mean ZC interval or the mean ZC rate may not be appropriate for processing against sinusoidal interference that is stronger than the desired signal. For the sinusoidal signal plus Gaussian noise case, several ZC statistics, including the mean ZC interval and the standard deviation of ZC intervals, were calculated. It was found that a processor utilizing these statistics can be effective when the input SNR (signal‐to‐noise ratio) is greater than −14 dB.

ISSN:0001-4966    

DOI:10.1121/1.384261

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP