scholarly journals The Magnitude of the Frequency Jitter of Acoustic Waves Generated by Wind Instruments Is of Relevance for the Live Performance of Music

Acoustics ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 411-424
Author(s):  
Alexander M. Rehm
Keyword(s):  
Acoustic Waves ◽  
Fold Increase ◽  
Acoustic Energy ◽  
Wind Instruments ◽  
Live Performance ◽  
Tenor Saxophone ◽  
Wind Instrument ◽  
Radiated Sound ◽  
Upper Register

It is shown that a gold-plated device mounted on a tenor saxophone, forming a small bridge between the mouthpiece and the S-bow, can change two characteristics of the radiated sound: (1) the radiated acoustic energy of the harmonics with emission maxima around 1500–3000 Hz, which is slightly reduced for tones played in the lower register of the saxophone; (2) the frequency jitter of all tones in the regular and upper register of the saxophone show a two-fold increase. Through simulated phase-shifted superimpositions of the recorded waves, it is shown that the cancellation of acoustic energy due to antiphase superimposition is significantly reduced in recordings with the bridge. Simulations with artificially generated acoustic waves confirm that acoustic waves with a certain systematic jitter show less cancelling of the acoustic energy under a phase-shifted superimposition, compared to acoustic waves with no frequency jitter; thus, being beneficial for live performances in small halls with minimal acoustic optimization. The data further indicate that the occasionally hearable “rumble” of a wind instrument orchestra with instruments showing slight differences in the frequency of the harmonics might be reduced (or avoided), if the radiated acoustic waves have a systematic jitter of a certain magnitude.

Folding Star-Shaped Acoustic Transducers for Real-Time Guidance of Radiated Acoustic Waves

2017 ◽  
Author(s):  
Chengzhe Zou ◽  
Ryan L. Harne
Keyword(s):  
Acoustic Waves ◽  
Shape Change ◽  
Signal Transmission ◽  
Sound Field ◽  
Digital Signal ◽  
Analytical Framework ◽  
Acoustic Energy ◽  
Acoustic Transducers ◽  
Theoretical Predictions ◽  
Radiated Sound

Directed acoustic energy is used throughout medical practices, scientific research, and engineering applications. Conventionally, arrays of transducer constituents are assembled and driven with inputs that are determined by digital signal processing methods, which guides the acoustic waves for signal transmission and reception purposes. Beamforming is the term for this approach, although inherent limitations of stability and computational efficiency hinder the outcomes. Recent efforts have revealed the broad merits of folding origami-inspired acoustic array architectures so that the transducer constituent and array shapes change, giving rise to direct control of acoustic energy radiation characteristics. Because the design of the origami tessellation used to create the array is pivotal to the adaptive acoustic energy steering, a new star-shaped foldable transducer is studied in this work for its unique inward and outward shape change characteristics. In order to facilitate this investigation, an analytical framework is developed to identify the connections between the folding-induced topology and radiated sound field. The high-fidelity boundary element method verifies the analytical model while experimental efforts validate the theoretical predictions. The adaptation of radiated sound pressure from the star-shaped transducer is shown to be several orders of magnitude, which illustrates its great potential in acoustic energy guidance and prospective applications.

Laser-Induced Acoustic Waves for Measurement and Imaging

2000 ◽  
Author(s):  
Wen Li ◽  
Ronald A. Roy ◽  
Robin O. Cleveland ◽  
Lawrence J. Berg ◽  
Charles A. DiMarzio
Keyword(s):  
Acoustic Waves ◽  
Peak Power ◽  
Laser Light ◽  
Short Pulse ◽  
Laser Wavelength ◽  
Acoustic Imaging ◽  
Acoustic Energy ◽  
High Peak Power ◽  
First Case ◽  
Very High

Abstract A short pulse of laser light can act as a source of acoustic energy for acoustic imaging. Although there are a number of mechanisms by which the light pulse may generate sound, all require a pulse of high peak power density and short duration. In this work, we address examples where the material is highly absorbing at the laser wavelength, and the sound is generated near the surface. In these cases, there exist two different mechanisms which can convert the light to sound. The first is heating followed by expansion, and the second is generation of a plasma in the air above the surface. In the first case, sound generation occurs in the medium of interest and the energy efficiency can be very high, in the sense that no reflection losses occur. We present two applications from our own research.

Laser-Based Ultrasound Interrogation of Surface and Sub-Surface Features in Advanced Manufacturing Materials

2021 ◽  
Author(s):  
Kathryn Jinae Harke ◽  
Nicholas Calta ◽  
Joseph Tringe ◽  
David Stobbe
Keyword(s):  
Acoustic Waves ◽  
Surface Defects ◽  
Surface Acoustic Waves ◽  
Acoustic Energy ◽  
Advanced Manufacturing ◽  
Powder Bed ◽  
Surface Features ◽  
Performance Targets ◽  
All Optical ◽  
X Ray Computed

Abstract Structures formed by advanced manufacturing methods increasingly require nondestructive characterization to enable efficient fabrication and to ensure performance targets are met. This is especially important for aerospace, military, and high precision applications. Surface acoustic waves (SAW) generated by laser-based ultrasound can detect surface and sub-surface defects relevant for a broad range of AM processes, including laser powder bed fusion (LPBF). In particular, an all-optical SAW generation and detection configuration can effectively interrogate laser melt lines. Here we report on scattered acoustic energy from melt lines, voids, and surface features. Sub-surface voids are also characterized using X-ray Computed Tomography (CT). High resolution CT results are presented and compared with SAW measurements. Finite difference simulations inform experimental measurements and analysis.

scholarly journals APLIKASI PEMBELAJARAN PERALATAN TANJIDOR BERBASIS ANDROID

JOUTICA ◽  
2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Yusuf Permadi ◽  
Nur Nafiiyah
Keyword(s):  
Operating System ◽  
Musical Instruments ◽  
Wind Instruments ◽  
Entertainment Media ◽  
Snare Drum ◽  
Space And Time ◽  
Wind Instrument ◽  
Technological Developments ◽  
Narrow Space

Smartphone is the manifestation of the technological developments that can narrow space and time. Smartphone is not only used as a means of communication but as a means of entertainment for many kinds of applications that is presented by the developers. Android is an operating system that is widely used by several manufacturers of smartphones today. Application is a program which is designed to perform a function with specific goals and purposes. Tanjidor is the musical art of Betawi. Tanjidor did not come originally from Indonesia, but from Portuguese language in a word Tangedor which means “stringed musical instruments”. Tanjidor itselfis played in several musical instruments category, namely wind instruments (in particular instrument it is called as mouthpiece) like clarinet, trombone, tuba, saxophone, and trumpet. In addition, there is also wind instrument musical which played by hit it (in a particular type it is called a percussion), like snare drum, tenor drum, bass drum, cymbals and drums. Android-based Tanjidor equipment learning application is used as the entertainment media and also aims to preserve the Indonesian art heritage by inserting Tanjidor instruments in Android smartphon. Therefore, Tanjidor musical art does not disappear over the time.

scholarly journals SCIENTIFIC AND PEDAGOGICAL DEVELOPMENTS IN THE FIELD OF SOUND FORMATION ON WIND INSTRUMENTS

2020 ◽  
Vol 2 (2(71)) ◽  
pp. 15-17
Author(s):  
Olga V. Uvarova
Keyword(s):  
Performing Arts ◽  
Wind Instruments ◽  
Pedagogical Practice ◽  
Highly Qualified ◽  
Wind Instrument ◽  
Priority Direction ◽  
The Subject ◽  
The Voice ◽  
Main Factor ◽  
Scientific Achievements

The priority direction in modern conditions of musical and pedagogical activity is the training of highly qualified specialists. The main factor of successful methodological work in the field of wind instrument performance is the study of scientific achievements in physiology, pedagogy, and psychology. Currently, in the pedagogical practice of wind art, there are a number of issues that require a conceptual understanding of the physiological components of the voice and articulation apparatus, as well as the dependence of sound quality on these organs. The subject of the analysis is the correct functioning of the larynx as a resonator. The analysis of scientific and theoretical developments in the field of sound formation on wind instruments allowed us to explain a number of pedagogical approaches in the practice of musical and performing arts

FLOWS OF VISCOUS COMPRESSIBLE FLUIDS UNDER STRONG STRATIFICATION: INCOMPRESSIBLE LIMITS FOR LONG-RANGE POTENTIAL FORCES

2011 ◽  
Vol 21 (01) ◽  
pp. 7-27 ◽  
Author(s):  
EDUARD FEIREISL
Keyword(s):  
Mach Number ◽  
Acoustic Waves ◽  
Stokes System ◽  
Hybrid Methods ◽  
Singular Limit ◽  
Acoustic Energy ◽  
Compressible Fluids ◽  
Navier Stokes ◽  
Whole Space ◽  
Rage Theorem

We study the singular limit of the compressible Navier–Stokes system in the whole space ℝ3, where the Mach number and Froude number are proportional to a small parameter ε → 0. The central issue is the local decay of the acoustic energy proved by means of the RAGE theorem. The result is quite general and the proposed approach can be applied to a large variety of problems that concern propagation of acoustic waves in compressible fluids. In particular, the method can be used for showing stability of various numerical schemes based on the so-called hybrid methods.

Fast Inertial Microfluidic Actuation and Manipulation Using Surface Acoustic Waves

2010 ◽  
Author(s):  
Leslie Y. Yeo ◽  
James R. Friend
Keyword(s):  
Acoustic Waves ◽  
Substrate Surface ◽  
Surface Acoustic Waves ◽  
Nanoparticle Synthesis ◽  
Fluid Flows ◽  
The Body ◽  
Acoustic Energy ◽  
Liquid Jets ◽  
Micron Diameter ◽  
Drop Interface

Though uncommon in most microfluidic systems due to the dominance of viscous and capillary stresses, it is possible to drive microscale fluid flows with considerable inertia using surface acoustic waves (SAWs), which are nanometer order amplitude electro-elastic waves that can be generated on a piezoelectric substrate. Due to the confinement of the acoustic energy to a thin localized region along the substrate surface and its subsequent leakage into the body of liquid with which the substrate comes into contact, SAWs are an extremely efficient mechanism for driving fast microfluidics. We demonstrate that it is possible to generate a variety of efficient microfluidic flows using the SAW. For example, the SAWs can be exploited to pump liquids in microchannels or to translate free droplets typically one or two orders of magnitude faster than conventional electroosmotic or electrowetting technology. In addition, it is possible to drive strong microcentrifugation for micromixing and bioparticle concentration or separation. In the latter, rich and complex colloidal pattern formation dynamics have also been observed. At large input powers, the SAW is a powerful means for the generation of jets and atomized aerosol droplets through rapid destabilization of the parent drop interface. In the former, slender liquid jets that persist up to centimeters in length can be generated without requiring nozzles or orifices. In the latter, a monodispersed distribution of 1–10 micron diameter aerosol droplets is obtained, which can be exploited for drug delivery and encapsulation, nanoparticle synthesis, and template-free polymer array patterning.

Multi-Modal Acoustic Flow Decomposition Examined in a Hard Walled Cylindrical Duct

2015 ◽  
Vol 39 (2) ◽  
pp. 289-296 ◽  
Author(s):  
Stefan Weyna ◽  
Witold Mickiewicz
Keyword(s):  
Acoustic Waves ◽  
Sound Propagation ◽  
Practical Interest ◽  
Sound Intensity ◽  
Wide Band ◽  
Acoustic Energy ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Circular Duct ◽  
Duct Geometry

Abstract Flow fields could be of great interest in the study of sound propagation in aeroengines. For ducts with rigid boundaries, the fluid-resonant category may contribute significantly to unwanted noise. An understanding of the multi-modal propagation of acoustic waves in ducts is of practical interest for use in the control of noise in, for example, aero-engines, automotive exhaust and heating or ventilation systems. The purpose of our experiments was to test the acoustic energy transmission of duct modes based on studies carried out by the sound intensity technique. Sound intensity patterns in circular duct are discussed of modal energy analysis with particular reference to proper orthogonal decomposition and dynamic mode decomposition. The authors try to justify some advantages of the sound intensity experimental research in this area. In the paper, the wide-band sound signal propagated from source approximated with loudspeaker in hard-walled duct is imaged using a sound intensity - based approach. For a simple duct geometry, the sound intensity field is examined visually and by performing a modal decomposition greater insight into the acoustic structures is obtained. The image of sound intensity fields below and above “cut-off” frequency region are found to compare acoustic modes which might resonate in duct.

Theoretical investigation of unsteady flow interactions with a premixed planar flame

2001 ◽  
Vol 435 ◽  
pp. 289-303 ◽  
Author(s):  
TIM LIEUWEN
Keyword(s):  
Flame Front ◽  
Acoustic Field ◽  
Acoustic Waves ◽  
Flame Speed ◽  
Acoustic Energy ◽  
Qualitative And Quantitative ◽  
Flow Interactions ◽  
Vorticity Production ◽  
Dissipation Processes ◽  
Release Processes

This paper presents the results of a theoretical study of the interactions between a laminar, premixed flame front and a plane acoustic wave. Its objective is to elucidate the processes that damp or drive acoustic waves as they interact with flames. Using linear analysis, the characteristics of the acoustic field, the flame's movement and wrinkling in response to acoustic perturbations, and the acoustic energy that is produced or dissipated at the flame are calculated. These calculations show that the net acoustic energy flux out of the flame is controlled by competing acoustic energy production and dissipation processes. Energy is added to the acoustic field by unsteady heat release processes resulting from the unsteady flux of unburned reactants through the flame by fluctuations in the flame speed or density of the unburned reactants. Energy is dissipated by the transfer of acoustic energy into fluctuations in vorticity that are generated at the flame front because of the misaligned fluctuating pressure and mean density gradients (i.e. the baroclinic vorticity production mechanism). The paper concludes by showing how these results can be generalized to determine the response of planar flames to an arbitrarily complex acoustic field. The principal contribution of this work is its demonstration that the excitation of vorticity and fluctuations in the flame speed have significant qualitative and quantitative affects on the interactions between flames and acoustic waves.

scholarly journals Microscale concert hall acoustics to produce uniform ultrasound stimulation for targeted sonogenetics in hsTRPA1-transfected cells

2021 ◽  
Author(s):  
Aditya Vasan ◽  
Florian Allein ◽  
Marc Duque ◽  
Uri Magaram ◽  
Nicholas Boechler ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Focused Ultrasound ◽  
Electrical Response ◽  
Fold Increase ◽  
Normal Brain ◽  
Ultrasound Exposure ◽  
Ultrasound Stimulation ◽  
Normal Brain Function ◽  
Ultrasound Intensity ◽  
The Brain

The field of ultrasound neuromodulation has rapidly developed over the past decade, a consequence of the discovery of strain-sensitive structures in the membrane and organelles of cells extending into the brain, heart, and other organs. Notably, clinical trials are underway for treating epilepsy using focused ultrasound to elicit an organized local electrical response. A key limitation to this approach is the formation of standing waves within the skull. In standing acoustic waves, the maximum ultrasound intensity spatially varies from near zero to double the mean in one half a wavelength, and can lead to localized tissue damage and disruption of normal brain function while attempting to evoke a broader response. This phenomenon also produces a large spatial variation in the actual ultrasound exposure in tissue, leading to heterogeneous results and challenges with interpreting these effects. One approach to overcome this limitation is presented herein: transducer-mounted diffusers that result in spatiotemporally incoherent ultrasound. The signal is numerically and experimentally quantified in an enclosed domain with and without the diffuser. Specifically, we show that adding the diffuser leads to a two-fold increase in ultrasound responsiveness of hsTRPA1 transfected HEK cells. Furthermore, we demonstrate the diffuser allow us to produce an uniform spatial distribution of pressure in the rodent skull. Collectively, we propose that our approach leads to a means to deliver uniform ultrasound into irregular cavities for sonogenetics.

Sign in / Sign up

Export Citation Format

Share Document