Digitalizing sound in your personal space

Design specifications for appliances are usually in the context of standard acoustic rooms like anechoic (full or hemi) and sometimes reverberant. However in the world of infotainment industry the devices are operated in your personal space - a generic environment like that of a living room and they continuously interact with other devices in real time. One has to take into account the scattering and absorption of sound from different surfaces and how they constructively and destructively interfere in generating a signature sound for the room and the devices. This environmental impact increases the design space significantly and makes it impractical to consider physical prototyping and testing. Simulating the acoustic behavior of the devices in a room environment has been attempted in the past and were successful only for lower frequency ranges or for smaller rooms. High end Multipole BEM and FEM Adaptive Order technologies have emerged in the recent past and together with parallel cloud computing make the modeling of generic room environment more feasible, up to a few kHz given adept hardware setup. A different, more asymptotic method like Ray Tracing provides a real breakthrough here and enables taking on the full audible frequency range and large rooms, in at least one order of magnitude faster solving times compared to the more conventional FEM and BEM method, which further supports optimization possibilities for different configurations in reasonable time.

Analytical model of the diffuse sound transmission loss of finite double panel structures

An analytical model for the forced sound transmission loss of finite single-leaf walls using a variational technique was previously developed and validated. As the double panel is one of the most used structures in building acoustics, the aim of this paper is to extend the analytical model to consider double panel structures. Analytical formulas for the forced part of the airborne sound insulation of finite sized double panel structures are derived using a variational technique based on the integral-differential equation of the fluid loaded panels. The formulas are valid in the entire audible frequency range. The results are compared to alternative analytical models and measurements, with reasonable agreement.

Modeling, Simulation and Performance Analysis of Multichannel Mems Piezoelectric Cantilevers for Cochlear Implantable Module

This work presents the enhanced area-efficient Multi-channel MEMS (Micro-Electrical Mechanical System) piezoelectric cantilever device (PCD) for a fully cochlear implantable sensor that works within the audible frequency range of 300-4800 Hz. The sound pressure level (SPL) of 95 dB, 100 dB, and 110 dB input is given in order to resonates the audible frequency range of the device which is placed on the eardrum. This stimulates the auditory nerve via the cochlea to send information to the brain. As a result, the Multi-channel MEMS piezoelectric cantilever device generates the highest potential voltage of 870 mV at 110-dB SPL and is detected under the excitation of 300 Hz. The output parameters such as von Mises stress, displacement, and the complete frequency bandwidth performance are analyzed using COMSOL Multiphysics.

Sound Absorption Properties of Materials Based on Recycled Plastic Granule Mixtures

This article reports on impedance tube measurements of the sound absorption coefficient α (-) of selected recycled foam plastics, i.e., ethylene-vinyl acetate (EVA), polyvinyl chloride (PVC), polystyrene (PS), and polypropylene (PP), in different mixtures with a binding adhesive. The effect of the thickness of the sample on the sound absorption spectrum as well as the variability in absorption across the different samples of the same composition and thickness are discussed. For the EVA/ PP and PS/PP mixtures, the spectrum is characterized by two peaks that shift as the thickness is changing. These mixtures were also found to be the most absorbent across the whole audible frequency range.

METHODS OF MUSIC THERAPY AND EXPERIMENTAL STUDY OF BIOELECTRICAL ACTIVITY OF STUDENTS' BRAINS WHILE LISTENING TO THE MUSICAL COMPOSITION OF THE AUDIBLE FREQUENCY SPECTRUM

The object of the study. Experimental research of music therapy methods. The problem to be solved. Determining the influence of selected musical composition of the audible frequency spectrum on the bioelectrical activity of students' brains, in particular alpha-, beta- and theta-rhythms. Main scientific results. The dependence of the influence on the bioelectrical activity of the brain of the compositions of the three frequency bands both individually and the composition as a whole is revealed. The dependence of alpha, beta and theta rhythms is shown. The area of ​​practical use of the research results. Medical institutions specializing in the treatment of disorders of the central nervous system, organic brain damage, stress, and its effective psychological rehabilitation. An innovative technological product. A technique of music therapy that allows to determine how different frequency ranges affect the bioelectrical activity of the human brain. The area of application of an innovative technological product. Clinical practice of using a music therapy.

Student Sensor Lab at Home: Safe Repurposing of Your Gadgets

The COVID-19 pandemic imposed various restrictions on the accessibility of conventional teaching laboratories. Enabling learning and experimenting at home became necessary to support the practical element of students’ learning. Unfortunately, it is not viable to provide or share a fully featured sensor lab to every student because of the prohibitive costs involved. Therefore, repurposing electronic devices that are common to students can bring about the sought-after practical learning experience without the hefty price tag. In distinction to the conventional lab instruments, however, consumer-grade devices are not designed for use with external sensors and/or electronic circuitry. They are not professionally maintained, do not undergo periodic safety tests, and are not calibrated. Nevertheless, nearly all modern computers, laptops, tablets or smartphones are equipped with high-quality audio inputs and outputs that can generate and record signals in the audible frequency range (20 Hz–20 kHz). Despite cutting off the direct currents completely, this range might be sufficient for working with a variety of sensors. In this presentation we look at the possibilities of making sure that such repurposing by design prevents any potential harm to the learner and to her or his personal equipment. These features seem essential for unsupervised lone experimenting and avoiding damage to expensive devices.

Simulation of Fabry-Perot Resonance for 3D Printable Complex Holey Acoustic Metamaterials

An acoustic metamaterial is a kind of material that is artificially designed in such a way that it can manipulate, control and direct sound waves. To date, various designs for acoustic metamaterials in the imaging applications have been proposed. However, these designs are generally simple due to the restriction from conventional manufacturing methods. By taking advantage of the additive manufacturing (AM) techniques, many complex acoustic metamaterials could be realized. However, the research on the complex structures for imaging applications has been very limited. In this paper, various 3D printable holey structured metamaterials with only one aperture are proposed, and the application possibility for sub-wavelength acoustic imaging in the audible frequency range is investigated. By using numerical simulation method, the effect of transmission properties of incident evanescent waves is analyzed to see whether these waves can completely transmit through the metamaterial. The phenomenon of Fabry-Perot resonances (FPR) that occur inside the hole for five different aperture shapes which are air-filled is studied, and the possibility of operating in a broadband resonance condition for the five designs are analyzed. These results can also be used to obtain valuable information for realizing a broadband acoustic hyperlens, which is an emerging application of 3D printable acoustic metamaterials.

Transmission control of acoustic metasurface with dumbbell-shaped double-split hollow sphere

Complex structures, large size and limited manipulation of acoustic waves are the problems that restrict the development of acoustic metasurfaces. Here, we report a transmission-type acoustic metasurface based on local resonance mechanism, which is composed of meta-atomic units called dumbbell-shaped double-split hollow spheres (DSDSHS). This metasurface with subwavelength scale has the advantage of simple structure and easy preparation, and can realize the full manipulation of sound waves. Negative refraction with different transmission angles and high intensity plate focusing lens are realized in the air environment of audible frequency. The proposed metasurface has potential applications in the miniaturization and integration of sound transmission and sound energy collection, opening a new opportunity for manipulation of acoustic wavefront.