摘要:

The substitution method was adopted from industrial acoustics (Francois and de Montussaint 1972) to “eliminate the influence of the environment” on measurements of the amplitude of vocalizations given by blue monkeysCercopithecus mitisand grey-cheeked mangabeysCercocebus albigena.Measurements were conducted of sound power and sound pressure level of representative utterances. Monkey vocal radiation patterns were also measured. The results showed that vocal amplitude ranged from 62 dB to 100 dB in sound pressure (re 1 pw). At a distance of 2 m, the loudest calls approached an amplitude of 110 dB SPL, a level about equal to the loudest human yell. The measurements of call amplitude conducted here exceeded those derived from the field by approximately 10 dB. It was shown that the discrepancy in amplitude between these laboratory based measurements and earlier measurements conducted under field conditions (Waser and Waser 1977) was probably due to destructive interference between the direct wave and the “ground wave”, a phase shifted wave reflected from the ground. Measurements of radiation patterns of primate vocalizations showed that, like human speech, directivity was a function of frequency, with high-frequency components being radiated more directionally than lower-frequency components. However, primate utterances were in general radiated more omnidirectionally than was human speech.

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753099

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Seasonal changes of parameters of full song were studied in a free-living population of chaffinchesFringilla coelebsduring one entire reproductive period. Approximately 7000 strophes sung by 14 male chaffinches were recorded and analysed by sonography and a particular oscillographic method. While the general pattern of song strophes, i.e. characteristics of elements, number and arrangement of phrases, and final flourish, remained constant throughout the reproductive period, full song varied with respect to the repetition rate of strophes, number of strophe types used, intensity of singing, duration of strophes, and percentage of incomplete strophes sung. These changes are discussed as results of learning processes, social interactions in the population, and endogenous mechanisms activating memorized information.

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753100

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The mechanism of sound production in tettigoniids is examined by applying the method of ‘cepstrum’ analysis to insect calls. The power cepstrum is defined as the inverse Fourier transform of the logarithmic power spectrum. This analysis shows that the tettigoniid sound signal is a convolution in time of probably two components. The first is caused by the initial impact of teeth of the stridulatory file on the left wing against the plectrum on the right wing (termed the input pulse); the second is caused by the oscillating properties of the tegmina (these being a function of the intrinsic frequencies of dorsal fields and mirror and their damping properties). In the cepstrum each component appears as a varying number of peaks. The tooth impacts cause a very low quefrency peak probably representing the time in which the two tegmina are in contact during each impact and high quefrency peaks representing the impulse repetition rate. The oscillating properties of the tegmina cause two major quefrency peaks which can be clearly related to the size of the dorsal fields and of the mirror respectively, and therefore to their intrinsic frequencies. The high damping factor of the tegmina together with the transient shape of the tegminal input pulse causes a strong time limitation of the impulses and is therefore responsible for the broad frequency bands occurring in the power spectra of the tettigoniid songs. The impulse generation of a synthetic tettigoniid song is discussed.

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753101

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753102

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753103

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753104

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753105

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753106

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753107

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0952-4622    

DOI:10.1080/09524622.1989.9753098

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor