摘要:

A design of a nonspherical acoustic lens and its test results are presented. The lens has elliptic surfaces to eliminate on‐axis spherical aberration. The lens was designed with the aid of third‐order aberration theory. Acoustic lenses with nonspherical surfaces are easily manufactured and should prove to be a valuable addition to single or multiple element lens systems.

ISSN:0001-4966    

DOI:10.1121/1.383896

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Errata and addenda to the paper referenced in the title are presented. A discussion of certain limiting conditions for the insertion loss of the baffle against flexural waves is also included.

ISSN:0001-4966    

DOI:10.1121/1.383897

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Whirling (nonplanar) motions of a base‐excited cantilever have been recently investigated by Crespo da Silva and Glynn. Some erroneous conclusions, pointed out here, have been reported in thisJournalby another author [J. Acoust. Soc. Am. 65, 931–939 (1979)] when reproducing an earlier paper written by Haight and King in 1972 [J. Acoust. Soc. Am. 52, 899–911 (1972)]. The results reported here are confirmed by numerical integration of the nonlinear integro‐differential equations of motion.

ISSN:0001-4966    

DOI:10.1121/1.383899

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

There exist in the literature three attempts to derive basilar membrane travel times from the phase versus frequency characteristics of responses to tones in the auditory nerve [Andersonetal., J. Acoust. Soc. Am. 49, 1131–1139 (1971)], cochlear nucleus [Gibsonetal., inPsychophysicsandPhysiologyofHearing, edited by Evans and Wilson (Academic, New York, 1977), pp. 57–68], and basilar membrane [Roblesetal., J. Acoust. Soc. Am. 59, 926–939 (1976)]. It is argued in this paper that these derivations probably have overestimated the actual mechanical travel times. Travel time was originally defined by von Békésy as the latency between the onset of a click stimulus and the onset of basilar membrane vibration. For a linear bandpass system, the frequency‐domain equivalent of this latency is the high‐frequency asymptotic slope of the phase lag versus frequency characteristic, which is not generally a linear function. In the neural studies (auditory nerve and cochlear nucleus) it was assumed that the phase versus frequency characteristic was a straight line. Slopes derived under a linear assumption are probably closer to the weighted average group delay (i.e., thecenterofgravityof the click response) than they are to travel time. In the Mössbauer study of basilar membrane mechanics the latency of the response to clicks was compared with the low‐frequency slope of the phase characteristic. The comparison should have been made with thehigh‐frequencyslope.

ISSN:0001-4966    

DOI:10.1121/1.383900

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Previous research has shown that a signal which may be one of two pure tones will be less detectable than a signal that is of constant, known frequency. In the present study, the effect of waveform uncertainty was evaluated by using pulse‐train signals with identical power spectra but different phase spectra. Results for a group of 11 listeners suggest that when differences in the energy spectra of signals are eliminated, signal uncertainty has, at best, a small effect on detection performance.

ISSN:0001-4966    

DOI:10.1121/1.383901

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

By storing a digital representation of the impulse response of an equivalent filter in a digital memory, a set of musical tones can be generated in which every tone in the set has the same spectral envelope rather than the same waveshape as occurs when the waveshape, itself, is stored digitally. When the impulse response is stored, rather than the waveshape, completely arbitrary attack characteristics can be obtained including inharmonic and noise components. The impulse response that is required to synthesize any existing periodic tone, including the attack portion, can be derived by shifting the original tone one pitch period and subtracting the shifted tone from the original.

ISSN:0001-4966    

DOI:10.1121/1.383902

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

The radiation reactance of a small magnetostrictive transducer at an air–water surface was measured in the presence of a hollow and then a solid sphere placed in the water. The sphere was placed in the water directly below the transducer and on its radiation axis. Measurements were taken as a function of the sphere’s depth in the water. A measurable effect is observed for depths of two wavelengths or less.

ISSN:0001-4966    

DOI:10.1121/1.383903

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

摘要:

Some observations on Duncan’s theoretical development are made and a shortened alternative analysis presented.

ISSN:0001-4966    

DOI:10.1121/1.383904

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.384478

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.383905

出版商:Acoustical Society of America    

年代:1980

数据来源: AIP