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Sea lamprey (Petromyzon marinus) are invasive in the Laurentian Great Lakes and parasitically feed on valued fishes. Migration barriers and selective pesticides are used to control sea lamprey, but there is a desire to develop additional control tools such as traps with nonphysical deterrents. Sound has been used as a deterrent for other invasive species, but its potential for manipulating sea lamprey behavior in natural stream conditions remains untested. Here, behavioral responses of upstream-migrating adult sea lamprey in response to low frequency sounds of 70 or 90 Hz was tracked in a small stream (8 m wide) using passive integrated transponder (PIT) telemetry. The low frequency sounds shifted sea lamprey distribution, with up to 30% more sea lamprey detected on PIT antennas without sound compared with PIT antennas with sound playing. Future studies could continue testing low frequency sounds in larger rivers with larger speakers for use as a natural deterrent at sea lamprey barriers to push sea lamprey toward traps. Les lamproies marines (Petromyzon marinus) sont envahissantes dans les Grands Lacs laurentiens et se nourrissent en parasitant de nombreux poissons ayant une valeur economique. Des barrieres a la migration et des pesticides selectifs sont utilises pour controler les lamproies, mais il est souhaitable de mettre au point d'autres outils de lutte contre l'espece, comme des pieges jumeles a des repulsifs non materiels. Le son a ete utilise comme repulsif pour d'autres especes envahissantes, mais sa capacite de modifier le comportement des lamproies dans des conditions naturelles de cours d'eau n'a pas encore ete validee. Les reactions comportementales de lamproies adultes en montaison a des sons de basse frequence, de 70 Hz ou 90 Hz, ont ete surveillees dans un petit cours d'eau (de 8 m de largeur) par suivi telemetrique de radioetiquettes passives integrees (PIT). Les sons de basse frequence ont modifie la repartition des lamproies, les antennes PIT qui ne diffusaient pas de sons ayant detecte jusqu'a 30 % plus de lamproies que les antennes diffusant ces sons. Des etudes futures pourraient poursuivre la mise a l'essai de sons de basse frequence dans de plus grandes rivieres, avec des haut-parleurs plus imposants, pour utilisation comme repulsif naturel aux emplacements de barrieres a lamproies, afin d'aiguiller ces dernieres vers des pieges. [Traduit par la Redaction], Introduction Sea lamprey (Petromyzon marinus) are highly invasive in the Laurentian Great Lakes and require a multinational control effort to suppress their population and allow native species recovery (Christie and [...]

Sound can be an argument. To make this claim, this essay eschews traditional formalist definitions of argument in favor of Wayne Brockriede's perspectivem. I focus on how sound satisfies the three conditions of argumentation: inference, choice, and common value framework. Then, I outline three unique features of sound argument: it is embodied, immediate, and immersive. These unique features beget a style of reasoning that provokes visceral memories, conveys urgency, and attunes arguers. I also theorize three new criteria for evaluating sound reasonableness: force, velocity, and masking. Sound arguments may exert too much or too little force, occur at too quick or slow of a velocity, or may mask another's position. If a sound argument violates any or all three of these conditions, then it is no longer considered an argument. KEYWORDS Sound studies; argumentation theory; sound argument; Brockriede; perspectivem, Introduction In the early days of the 'visual turn,' many scholars appealed to the ubiquity of media, like television, to justify the expansion of the object domain. In their essay, [...]

'WHAT COUNTRY (FRIENDS) IS THIS?' asks the shipwrecked Viola as she comes ashore to Illyria in Twelfth Nights. (1) That question is neither raised, nor answered, in the play-text of [...]

I. Listening can only be localized in the ear by force of reduction. Imagine a room (call it the 'music room'), in which sounds are heard; any normal person entering [...]

The paper focuses on the reverberation chamber method for the shielding properties evaluation of equipment-level enclosures. The enclosure under test is numerically modeled by an in-house finite-difference time-domain code that is able to predict the field inside the enclosure and the voltage captured by the probe placed inside it. The chamber fields have been modeled by applying the plane-wave superposition. The code is validated by measurements in our reverberation chamber. Subsequently, the effect of probe positioning and length on the induced voltage is analyzed. Finally, the enclosure shielding effectiveness is evaluated by applying two different definitions, and a statistical analysis is carried out, thus allowing an estimation of the measurement uncertainty. Index Terms--Finite-difference time domain (FDTD), frequency stirring, plane-wave superposition, reverberation chamber, shielding effectiveness, small enclosures.

This paper presents a procedure for evaluating the performance of reverberation chambers, by approximating the maximum working volume in a given configuration. The evaluation of this volume is based on the geometrical and physical constraints, e.g., the ones related to the internal E-field distribution recommended by standards. The importance of the present work is related to the development of a non-canonical reverberation chamber configuration, whose excitation is carried out by transmission lines, instead of antennas plus paddles. Index Terms--Optimization, reverberation chambers, working volume.

Heard melodies are sweet, but those unheard Are sweeter; therefore, ye soft pipes, play on; Not to the sensual ear, but, more endear'd. Pipe to the spirit ditties of no [...]

This essay contributes to the decentring of vision that has been the project of much recent scholarship. Accepting derrida's argument in Of Grammatology that the sound of the voice is [...]

Jean-Luc Nancy begins his recent book A l' ecoute with a question about the nature of philosophy--a question that is potentially vexing, even dangerous, for philosophy, insofar as it concerns, [...]

A novel theoretical feasibility study to reverberate a large metallic chamber is proposed. The method is based on the displacement of a radiating antenna inside the chamber, and the reverberating effect is obtained by coupling the antenna current in different ways with the cavity modes. This technique eliminates mechanical rotating paddles inside the chamber and offers the advantage of a continuous-wave operation compared with the frequency stirring method. The reverberating characteristics of the proposed technique are evaluated by calculating the field statistics. The analyzed situation concerns a real antenna, and its radiation into the reverberation chamber is modeled using Green's function of cavity. The numerical problem is solved by the method of moment. The model has been tested and is able to rigorously characterize the reverberating environment for the design and optimization of antenna configurations to be addressed in future studies. Index Terms--Electromagnetic modeling, reverberation chamber (RC), source stirring.

With the proliferation of small electric devices in recent years, along with various other applications, there is a growing need to test and determine the shielding properties or shielding effectiveness (SE) of physically small (but electrically large) enclosures or cavities. In this paper, we discuss how a reverberation chamber technique can be used to measure the SE of such enclosures. The approach consists of placing the small enclosure inside a reverberation chamber and using frequency stirring to excite the reverberation chamber. A small surface probe (i.e., a monopole) is mounted on the inside wall of the small enclosure to measure the power level inside the small enclosure. We present measured data from various other reverberation chamber approaches obtained from various enclosure configurations. The data from these other reverberation chamber approaches are used to validate the proposed approach. We also compared measured data to theoretical calculations of the SE for two small enclosures with circular apertures. These various comparisons illustrate that the proposed technique is a valid approach for determining the SE of physically small (i.e., cubic enclosure dimensions of the order of 0.1 m and smaller), but electrically large enclosures (that support several modes at the lowest frequency of interest). Index Terms--Circular apertures, reverberation chamber, shielding effectiveness (SE), small cavities, small enclosure.

We derive theoretical and experimental performance based upper bounds for the rate of frequency scanning (sweeping) or electronic stirring inside a reverberation chamber. The interior field is modeled as a dynamic process of frequency modulation of the source field. The bounds are obtained by imposing quasi-stationarity of the field, as a requirement for preventing nonlinear distortion of an analog or digital excitation (test) signal injected into the chamber. Index Terms--Electromagnetic compatibility (EMC) measurements, frequency scanning, quasi-stationarity, reverberation chambers, signal distortion, signal integrity.

The common assumption about music is that unlike visual arts that include several genres, music is the universal or only art of sound. A case is made for non-musical arts of sound and conceptual reasons why music and soundart need to be separated are presented.

This paper proposes a biologically inspired and technically implemented sound localization system to robustly estimate the position of a sound source in the frontal azimuthal half-plane. For localization, binaural cues are extracted using cochleagrams generated by a cochlear model that serve as input to the system. The basic idea of the model is to separately measure interaural time differences and interaural level differences for a number of frequencies and process these measurements as a whole. This leads to two-dimensional frequency versus time-delay representations of binaural cues, so-called activity maps. A probabilistic evaluation is presented to estimate the position of a sound source over time based on these activity maps. Learned reference maps for different azimuthal positions are integrated into the computation to gain time-dependent discrete conditional probabilities. At every timestep these probabilities are combined over frequencies and binaural cues to estimate the sound source position. In addition, they are propagated over time to improve position estimation. This leads to a system that is able to localize audible signals, for example human speech signals, even in reverberating environments. Index Terms--Binaural hearing, probabilistic estimation, sound source localization.

This paper presents a study of coupling between an external field and a metallic enclosure with a long aperture in the frequency range which includes several box resonances. A reverberation chamber (RC) and an anechoic chamber (AC) are considered as a field generation structure. In both cases, a customized FDTD code is used to calculate the current induced by the external field in a loop placed inside the enclosure. In order to simulate the AC facility, a single plane wave is used to represent the test field, whereas for the RC, the field is represented by a proper superposition of random plane waves. Numerical results are experimentally validated. The proposed method is useful to investigate the performance of the enclosure during its early design stage before the realization of a prototype. Index Terms--Anechoic chambers (AC), FDTD methods, immunity, reverberation chambers (RC).

The behavior of a device in a reverberation chamber can be analyzed as the same device irradiated by random plane waves. This work proposes an application of the finite difference time domain method to analyze the device by using a superposition of random plane waves, simulating the behavior of a reverberation chamber. The analysis of a transmission line compared with theoretical and experimental results in a reverberation chamber is reported. Index Terms--Finite difference time domain (FDTD) methods, random plane wave generation, reverberation chambers, superposition of plane waves.

This paper describes an investigation into the key factors which contribute to an effective mode stirrer. The work concentrates on the lower frequency range, since all stirrers have poorer performance at low frequencies. The stirrer's shapes and sizes have been investigated, together with an optimization of the finer details in the stirrer's shape. The modeling of the mode stirred chamber has been performed using the transmission-line matrix (TLM) method. Software has been developed which, for each position of the rotating stirrer, builds the shape of the stirrer using thin, perfectly conducting boundaries. Results indicate that the design of the stirrer's basic shape has a small but significant impact on its performance. A genetic algorithm has been used to optimize certain parameters in the shape of the stirrer, and a fitness factor based on a free space model of the stirrer has been used. The free space model runs 1500 times faster than the model in the chamber. The optimization is shown to improve the stirrer's performance in three different sizes of chamber. Computer modeling has been verified by measurements performed in the chamber at the University of York. Index Terms--Genetic algorithms (GA), matrix methods, measurement, modeling, mode stirring, reverberation chamber, transmission line.

The paper investigates the possibility of reverberating a shielded room by means of source mode stirring. The transmitting antenna position and orientation are randomly changed inside a sub-volume of the chamber. In general, antenna displacement can be achieved by a proper design of an array of antennas, where one or more antennas are activated at different time instants. This technique eliminates mechanical rotating paddles inside the chamber, and offers the advantage of a continuous wave (CW) operation with respect to the frequency stirring method. The preliminary experimental and simulated results encourage further investigation of the proposed technique. Index Terms--Electronic stirring, reverberation chamber, source stirring.

A numerical model of wires in rectangular metal cavities is introduced for computing antennas in a simplified theoretical reverberation chamber. The code is based on the method of moments, and it uses the Ewald summation for efficient calculation of the cavity Green's function. The Q-value of the chamber is accounted for in the model by a homogeneous material filling the chamber. The S-parameters of two dipoles placed in many random positions in the cavity are computed and averaged to provide the average transfer function of the chamber. This represents mode stirring by moving the antennas, referred to as position stirring. The computed results are compared with theoretical statistical values as well as experimental results. The discrepancies are discussed. Index Terms--Cavities, Ewald transformation, Green's function, reverberation chamber.

By the use of a fifth-order weighted essentially nonoscillatory scheme to solve the two-dimensional, unsteady compressible Euler equations, a planar blast/vortex interaction is investigated in detail. The effects of the initial blast Mach number [M.sub.S] and vortex Mach number [M.sub.V] are discussed and compared with the corresponding cases of shock/vortex interaction. The sound generated by the planar blast/vortex interaction is also studied. It is found that the radial pressure peaks of the first sound for the cases of shock/vortex interaction are larger than those for the cases of blast/vortex interaction. However, the radial pressure peaks of the second sound in the blast/vortex interaction can be larger than those in the corresponding case of shock/vortex interaction. This is due to the effect of the secondary shock interacting with the vortex, enhanced by the expansion waves following the blast-wave front. In addition, an interesting phenomenon of the fourth sound, which is an exception from the first three sounds generated by the blast/vortex interaction, is found that does not occur in the case of a shock/vortex interaction.

Have you ever noticed that a song can sound very different depending on where you are hearing it? A live band may sound very different from a CD of the […]

Byline: A. S. Starkov (1) Abstract: The problem of the wave field of a source moving in an inhomogeneous medium is considered. It is assumed that the velocity of the source is less than the velocity of sound for t &lt 0 and is greater than this velocity for t &gt 0 (subsonicasupersonic transition). An asymptotic expansion for the wave field in a neighborhood of the source is constructed on the basis of the well-known Hadamard ansatz. The expansion derived is uniform with respect to the velocity of the source and contains new special functions. These functions are generalizations of the Hankel and Bessel functions and possess some remarkable properties. Bibliography: 7 titles. Author Affiliation: (1) St.Petersburg State University, Russia Article History: Registration Date: 12/10/2004

Research presents an axisymmetric model to explain the nonlinear acoustic properties of an orifice and show that they are closely related to the vortex shedding process seen at the edge of the orifice. Data show that the nonlinear acoustic reactance is inversely related to the amplitude of the sound pressure.

This article describes a frequency-domain discretization technique that allows a numerical solution for the equation controlling propagating small disturbances inside nonuniform potential flows. Application of the potential equation to arbitrary aerodynamic mean flow is discussed.

Our earlier work in Part 1 of this paper [1] is here extended to quadrupole distributions and point quadrupoles (i.e., stresses) in arbitrary motion. Radiation patterns are obtained and displayed in many relevant cases.

Byline: John P. Fraedrich (1), Maryon F. King (2) Abstract: This article reviews the concepts of nonmusical sound and noise with respect to sound elements, perception and interpretation. Following a review and synthesis of the literature, which has predominantly been conducted in non-marketing fields, practitioner and researcher implications are identified and discussed. Author Affiliation: (1) Department of Marketing, College of Business, Southern Illinois University, Carbondale, Illinois, 62929-4629 (2) Southern Illinois University, USA Article History: Registration Date: 28/09/2004

The continuous wavelet transform can be used to produce spectrograms which show the frequency content of sounds (or other signals) as a function of time in a manner analogous to sheet music. While this technique is commonly used in the engineering community for signal analysis, the physics community has, in our opinion, remained relatively unaware of this development. Indeed, some find the very notion of frequency as a function of time troublesome. Here spectrograms will be displayed for familiar sounds whose pitches change with time, demonstrating the usefulness of the continuous wavelet transform.

The paper aims to link up with that ideal line of debate concerning the application -- or applicability -- of semiotics in the field of music. Although it has been in existence and specifically studied for more than twenty years, musical semiotics still runs into fundamental problems, the resolution of which is not to be found simply in the generalization of specific principles, or in the departures from them allowed by those same principles. This is so much so that the problems tend to be ignored. Questions about the if and how of a potential process of semiosis in music therefore become -- both in these terms and actually -- a priority and epistemologically indispensable, given that one really wants to know how pertinent a semiotic approach to musical facts can be.

Recently published results arising from the acoustic noise control research community, demonstrate that system dynamics can be modified using feedforward control. Initial investigations applied to known disturbances in the form of steady-state harmonic excitation. This paper further explores feedforward dynamic modification, provides a proof of the nature of the modification, extends the method to allow for broadband excitation, and introduces a design technique for arbitrary assignment of transfer function poles. The results apply to any structure representable using modal expansion, and are applicable to systems with nonminimum phase zeros.

Sound and vibration transmission modeling methods are important to the design process for high quality automotive vehicles. Statistical Energy Analysis (SEA) is an emerging design tool for the automotive industry that was initially developed in the 1960's to estimate root-mean-square sound and vibration levels in structures and interior spaces. Although developed to estimate statistical mean values, automotive design application of SEA needs the additional ability to predict statistical variances of the predicted mean values of sound and vibration. This analytical ability would allow analysis of vehicle sound and vibration response sensitivity to changes in an algorithm to extend the design application of the SEA method through prediction of the variances of RMS, responses of vibro-acoustic automobile structures and interior spaces from variances in SEA automotive model physical parameters. The variance analysis is applied to both a simple, complete illustrative example and a more complex automotive vehicle example. Example variance results are verified through comparison with a Monte Carlo test of 2,000 SEA responses whose physical parameters were given Gaussian distributions with means at design values. Analytical predictions of the response statistics agree with the statistics generated by the Monte Carlo method but only require about 1/300 of the computational effort.

The control of pairing sound of two identical thin vortex rings was investigated through the use of a thin control vortex ring of opposite circulation. Amplification and attenuation of the pairing sound was seen. These were caused by the effect of the control vortex ring on the interaction of the two pairing rings. Four basic kinds of interaction of the three interacting vortex rings and different degrees of amplification and attenuation were determined.

The response and acoustic radiation of a panel structure forced by a constantly accelerating subsonic turbulent boundary layer with superimposed pure-tone sound were measured in a wind tunnel. Both panel loading and response showed convective instability and high-dimensional complex behaviors because of nonlinear coupling between the convective short-scale instability wave in the boundary layer and the localized intense long scales of the pure-tone sound and its harmonics. In each run, the panel response showed unique dynamics, revealing a dependency on the initial conditions found in a temporal chaotic system.

The two-dimensional flap side-edge flow model developed by R. Sen is examined to determine the noise-production capability of the suggested mechanism. The model assumes that a vortex will be created at the equilibrium position off the side edge of the flap. The vortex is then perturbed away from the equilibrium position by incoming turbulence, causing it to oscillate and to emit sound. The noise field is computed three-dimensionally by considering the flap to have a finite chord.

Several numerical algorithms for solution acoustic integrals that are applicable to acoustic analogy or Kirchoff method were utilized for external flow problems such as rotor noise. Prediction of rotor noise can be conducted with Kirchoff formulation, numerical, retarded-time, collapsing sphere, emission surface and solution adaptive algorithms. The retarded algorithms are the most robust and efficient type of formulation. On the other hand, solution adaptation enhances accuracy and reduces computational work.

Emphasizing physical pictures with a minimum of analysis, an introductory account is presented as to how vortices generate sound. Based on the observation that a vortex ring induces the same hydrodynamic (incompressible) flow as does a dipole sheet of the same shape, simple physical arguments for sound generation by vorticity are presented, first in terms of moving vortex rings of fixed strength and then of fixed rings of variable strength. These lead to the formal results of the theory of vortex sound, with the source expressed in terms of the vortex force [Rho](u [and] [Zeta]) and of the form introduced by Mohring in terms of the vortex moment (y [and] [Zeta][prime]), ([Rho] is the constant fluid density, u the flow velocity, [Zeta] = [nabla] [and] u the vorticity and y is the flow coordinate). The simple 'Contiguous Method' of finding the contiguous acoustic field surrounding an acoustically compact hydrodynamic (incompressible) field is also discussed. Some very simple vortex flows illustrate the various ideas. These are all for acoustically compact, low Mach number flows of an inviscid fluid, except that a simple argument for the effect of viscous dissipation is given and its relevance to the 'dilatation' of a vortex is mentioned.

An examination of the far-field hover acoustic features of the XV-15 aircraft with advanced technology blades provides a high-quality, far-field acoustics data base for a rotor tip speed range of 645-771 ft/s. Acoustic directivity features vary markedly with azimuth angles, particularly in forward quadrants. Sharp, positive pressure pulses that result from blade-vortex interactions propagate the aft of the aircraft and are intense at 45 degrees below the rotor plane.

Studies on nonlinear acoustics in combustion chamber partially reveal nonlinear behavioral patterns in stable systems. An approximate numerical method for stable systems involves the usage of differential equations for fluctuation time steps. Spatial and time averaging methods yield the differential equations for flow in two phases.