摘要:

Subjects were asked to match the lateral position of one tone, the “signal,” by means of another, the “pointer.” The two tones were presented alternately. The experimenter selected a combination of interaural time and intensity differences for the signal, and the subject adjusted the interaural time difference for the pointer until it seemed to him to be in the same lateral position as the signal. Subjects having normal hearing perceived the signal in two places, one strongly affected by the difference of level at the two ears, the other almost wholly dependent upon the difference of time.

ISSN:0001-4966    

DOI:10.1121/1.1908849

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

Dynamic magnetostrictive properties have been measured for nickel‐base alloys containing up to 10% cobalt, with from 0 to 6% chromium. The maximum value of electromechanical coupling coefficient 0.51 occurs in a binary alloy containing 4.5% cobalt, balance nickel, for which the magnetocrystalline‐anisotropy constant is zero. The maximum value of potential electroacoustic efficiency for resonance frequencies below 100 kc/sec is found, however, in a ternary alloy containing 1.4% cobalt, 2.3% chromium, balance nickel.It is concluded that the binary alloy is the most suitable material for the magnetostrictive element of receivers, such as hydrophones, particularly where a reasonably flat response is sought. The ternary alloy, because of its lower eddy‐current losses, is to be preferred for generating high‐frequency acoustic power.

ISSN:0001-4966    

DOI:10.1121/1.1908851

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

In places of high ambient‐noise level, the use of electrical devices as an aid to speech communication is sometimes precluded by safety requirements. A mechanical device may then be used provided that the individuals concerned are close to each other. Such a device can be made to incorporate all the acoustical benefits of a dose‐talking microphone. Sentence intelligibility tests showed that when the articulation index was zero for a nearby speech source the median subject obtained a score of 28% using ear covers alone and 84% with the sound transducer; the subjects with extreme scores improved from 0 to 14% and from 88 to 100% respectively. No subject using the device suffered a decrease in intelligibility.

ISSN:0001-4966    

DOI:10.1121/1.1908853

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

There are several major applications for intense audio sound fields: the outdoor propagation of speech and of warning signals, and the sonic fatigue testing of missile and aircraft components. In these applications, several factors combine to make it necessary to limit the portion of the frequency spectrum covered by any one loudspeaker unit. In order to provide adequate power capacity, selection is required between the alternatives of (a) using a large number of identical drivers, (b) using a plurality of drivers each especially designed for a selected portion of the frequency range, and (c) using combinations of these arrangements.In an array currently being used for sonic‐fatigue testing, a plurality of large open cone loudspeakers is used for low frequencies, and a plurality of horns is used for middle and high frequencies. Each horn is driven by several drivers.The driver voice coil and diaphragm proportions have been optimized to withstand fatigue stresses under the thermal conditions encountered. The driver is rated at 50‐w input for program material.Horn assemblies are available having throat arrays for mounting 6, 12, or 24 drivers. Various applications will be illustrated.

ISSN:0001-4966    

DOI:10.1121/1.1908855

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

Simultaneous pairs of four‐bit messages were presented to listeners at rates of two pairs every 4 sec (4 bits/sec), three pairs every 4 sec (6 bits/sec), four pairs every 4 sec (8 bits/sec), and six pairs every 4 sec (12 bits/sec). Each message of the pair was either [a] or [i], said by a male or a female, as a question (rising inflection) or a statement (falling inflection), and heard in either the right or the left ear.Sequences were made that were balanced (1) between ears, (2) between male and female voices, (3) between [a]'s and [i]'s and (4) between questions and statements. The subject sometimes listened to both messages but usually listened only for the messages (1) in one ear, (2) of one voice, (3) of one vowel sound, or (4) of one inflection.The best subject could receive correctly about 6 bits/sec whether this was one of two messages at the 12 bits/sec rate or both of two at the 6 bits/sec rate.

ISSN:0001-4966    

DOI:10.1121/1.1908857

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

The theory for the diffraction of light by plane ultrasonic waves of various standing wave ratios is derived. The liquid medium disturbed by the ultrasound is considered to act as an optical phase grating. By evaluating the diffraction integral for the light amplitude, expressions for the Doppler shift, the time dependent, and the time average light intensities are found for the diffraction spectrum. Experimental measurements using two adjacent ultrasonic waves progressing in opposite directions to simulate the desired optical phase grating indicate that the theory is valid.

ISSN:0001-4966    

DOI:10.1121/1.1908859

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

If two solids are coupled to each other through a liquid layer, transverse slip can occur at the boundary surface when an elastic wave is incident on the boundary. Algebraic expressions for the amplitudes of the various wave modes are derived on the assumption of transverse slip at the boundary, and these are compared with wave mode amplitudes for a solid‐air boundary. Experimental measurements in connection with the design of an indicator for the degree of coupling between an angle probe and a test object are explained on this assumption. Curves are given showing wave‐mode amplitude for: (i) Plexiglas‐air boundary; (ii) Plexiglas steel boundary assuming transverse slip; (iii) Plexiglas steel boundary assuming rigid contact.

ISSN:0001-4966    

DOI:10.1121/1.1908861

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

This paper describes a method of inversion of an integral equation arising the solution of the problem of reflection or refraction of a spherical sound‐wave pulse at a plane interface a layered elastic medium. The solution of this integral equation is equivalent to obtaining the inverse Laplace transform of the operational solution of the problem.

ISSN:0001-4966    

DOI:10.1121/1.1908863

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

The equation for the velocity of propagation of Rayleigh‐type surface waves in a porous, elastic, saturated solid is derived and discussed. The inertia coupling between fluid and solid is neglected, and Darcy's coefficient is taken to be independent of frequency.

ISSN:0001-4966    

DOI:10.1121/1.1908865

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1908867

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP