Acoustic communication is widespread in animals. According to the sensory drive hypothesis [Endler JA (1993) Philos Trans R Soc Lond B Biol Sci 340(1292):215-225], signals and perceptual systems have coevolved. A clear illustration of this evolution tetrapod middle ear, adapted life on land. Here we report discovery a bone conduction-mediated stimulation ear by wave propagation Sechellophryne gardineri, one world's smallest terrestrial tetrapods, which lacks yet produces acoustic signals....

Semi-anechoic rooms are used for the acoustic characterization of noise sources.They involve heavy infrastructures and thick absorbent lining.The purpose ongoing project "DADA" (Dôme Anti-Diffraction Acoustique) is to demonstrate a lower-cost alternative by supplementing thin passive lining with active technology.This targets an actual size functional demonstrator, important milestone before tackling fully anechoic room at Laboratory Mechanics Acoustics (LMA).Previous work has achieved...

This work concerns the theoretical analysis and synthesis of sound fields by a compact spherical loudspeaker array. Such an electroacoustic device consists several transducers mounted on sphere-like structure, which are driven independently in order to achieve non-uniform directivity patterns. The control strategy usually adopted is provide array with some preprogrammed basic directivities corresponding harmonic functions. Thus, arbitrary radiation pattern can be approximately achieved...

This paper evaluates the potential of field separation method (FSM) for performing subwoofer measurements in a small test room with poor absorbing properties, as is commonly available. The FSM requires knowledge both acoustic pressure and velocity fields on closed surface surrounding tested source. Pressures velocities, measured using p-p probe half-sphere mesh, are collected under various conditions: variable reverberation time (6.4–0.6 s) four measurement radii. data expanded spherical...

This paper deals with the acoustic modeling and measurement of a needle-to-grid plasma loudspeaker using negative Corona discharge. In first part, we summarize model described in previous papers, where electrode gap is divided into charged particle production region near needle drift which occupies most inter-electrode gap. each region, interactions between neutral particles ionized gas lead to perturbation surrounding air, thus generate an field. viewed as separate source, acoustical...

The acoustic pressure sensor described in this paper uses a small volume of ionized gas (plasma) as sensing element to receive energy from surrounding (air) set into oscillations by an disturbance. generation the is performed negative point-to-plane corona discharges. passage disturbance through disturbs flow charged particles between electrodes, and provokes current variation electrical system. This directly related pressure. An electroacoustic model plasma microphone proposed. From...

The “smart foam” concept and design originate from the combination of passive dissipation capability foam in medium high frequency ranges active absorption ability piezoelectric actuator (generally polyvinylidene fluoride) low range. This results into a passive/active control device that can efficiently operate over broad range frequencies. In this paper, full three dimensional finite element model smart is presented including its experimental validation. modeling tool uses quadratic...

Sound directivity control is made possible by a compact array of independent loudspeakers operating at the same frequency range. The drivers are usually distributed over sphere-like frame according to Platonic solid geometry obtain highly symmetrical configuration. radiation pattern spherical loudspeaker arrays has been predicted from surface velocity approximating membranes as rigid vibrating caps, although rigorous assessment this model not provided so far. Many aspects concerning...

The performance of cochlear implant (CI) listeners is limited by several factors among which the lack spatial selectivity electrical stimulation. Recently, many studies have explored use multipolar strategies where electrodes are stimulated simultaneously to focus field in a restricted region cochlea.These based on assumptions concerning properties inner ear that need validation. first, often implicit, assumption medium purely resistive and current waveforms produced sum linearly. second...

The measurement of the pressure field radiated by a sound source has many applications in fields noise control and loudspeaker system design. In this paper, radiation mode method is used to measure complex acoustic whose surface impedance arbitrary does not correspond Neumann boundary condition for calculation modes. most effective modes are as test functions calculate expansion around under test, an that matches measured at limited number points close source. This then greater distance...

This article presents the experimental implementation and results of a hybrid passive/active absorber (smart foam) made up from combination passive absorbent (foam) curved polyvinylidene fluoride (PVDF) film actuator bonded to rear surface foam. Various smart foam prototypes were built tested in active absorption experiments conducted an impedance tube under plane wave propagation condition at frequencies between 100 1500 Hz. Three control cases tested. The first case used fixed controller...

Comparison of loudspeakers is a major concern during design or product selection. There are several standards for the measurement loudspeaker characteristics, but none them provides hints rigorous comparison between devices. In this study, different ways evaluating acoustical dissimilarity were compared. Several methods signal analysis used, and each method metric two signals was defined. The correlation evaluations over significant panel led to identified classes measurements. A specific...

This study investigated the dimensions underlying perceived differences between loudspeakers. Listeners compared sound reproduction of 12 loudspeakers in a room, using three musical excerpts. For to be one just after other exactly same conditions, sounds radiated by were recorded listening and submitted paired comparisons headphones. The resulting perceptual dissimilarities analyzed multidimensional scaling technique, revealing two main used listeners discriminate These identical for As...