Immersive audio system based on 2.5D local sound field synthesis using high-speed 1-bit signal

2021 ◽  
Author(s):  
Kakeru Kurokawa ◽  
Yusuke Ikeda ◽  
Naotoshi Osaka ◽  
Yasuhiro Oikawa
Keyword(s):  
High Speed ◽  
Sound Field ◽  
Local Sound ◽  
Audio System ◽  
Immersive Audio

scholarly journals Measurement of the Local Sound Pressure on a Bias-Flow Liner Using High-Speed Holography and Tomographic Reconstruction

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 153466-153474 ◽  
Author(s):  
Andres E. Ramos Ruiz ◽  
Johannes Gurtler ◽  
Robert Kuschmierz ◽  
Jurgen W. Czarske
Keyword(s):  
High Speed ◽  
Sound Pressure ◽  
Tomographic Reconstruction ◽  
Bias Flow ◽  
Local Sound

Investigation of Pantograph Effect on High-Speed Train Noise

2012 ◽  
Vol 233 ◽  
pp. 239-242
Author(s):  
Xiao Feng Zhang ◽  
You Gang Xiao ◽  
He Lian Deng ◽  
Jian Feng Huang
Keyword(s):  
High Speed ◽  
Microphone Array ◽  
Broad Band ◽  
Side Wall ◽  
Sound Field ◽  
Noise Spectrum ◽  
Low Noise ◽  
Sound Insulation ◽  
Vehicle Noise ◽  
Sealing Performance

Using microphone and removable planar microphone array, the exterior and interior vehicle noise near pantograph were investigated when the train ran at 250-350km/h, the noise spectrum characters of these areas were obtained. The results show that at the pantograph seat and in the vehicle below pantograph, the noise spectrum show a broad band distribution, and the noise energy is mainly concentrated within the range of 100Hz-2kHz. Interior vehicle noise below pantograph is a non-uniform reverberant sound field, the regions with larger sound pressure level (SPL) are distributed near the roof, the floor, the side wall below the luggage. For reducing interior vehicle noise below pantograph, such measures as using low noise pantograph, adding sound insulation pad, filling sound absorption materials and improving sealing performance should be taken, and these measures should be effective at 100Hz-2kHz.

Local sound field reproduction using digital signal processing

1996 ◽  
Vol 100 (3) ◽  
pp. 1584-1593 ◽  
Author(s):  
Ole Kirkeby ◽  
Philip A. Nelson ◽  
Felipe Orduna‐Bustamante ◽  
Hareo Hamada
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Sound Field ◽  
Digital Signal ◽  
Local Sound

Fragmentation of acoustically levitating droplets by laser-induced cavitation bubbles

2016 ◽  
Vol 805 ◽  
pp. 551-576 ◽  
Author(s):  
Silvestre Roberto Gonzalez Avila ◽  
Claus-Dieter Ohl
Keyword(s):  
Shock Wave ◽  
Experimental Study ◽  
Surface Tension ◽  
Cavitation Bubble ◽  
High Speed ◽  
Size Range ◽  
Sound Field ◽  
Negative Pressures ◽  
Impulsive Pressure ◽  
Small Bubbles

We report on an experimental study on the dynamics and fragmentation of water droplets levitated in a sound field exposed to a single laser-induced cavitation bubble. The nucleation of the cavitation bubble leads to a shock wave travelling inside the droplet and reflected from pressure release surfaces. Experiments and simulations study the location of the high negative pressures inside the droplet which result into secondary cavitation. Later, three distinct fragmentation scenarios are observed: rapid atomization, sheet formation and coarse fragmentation. Rapid atomization occurs when the expanding bubble, still at high pressure, ruptures the liquid film separating the bubble from the surrounding air and a shock wave is launched into the surrounding air. Sheet formation occurs due to the momentum transfer of the expanding bubble; for sufficiently small bubbles, the sheet retracts because of surface tension, while larger bubbles may cause the fragmentation of the sheet. Coarse fragmentation is observed after the first collapse of the bubble, where high-speed jets emanate from the surface of the droplet. They are the result of surface instability of the droplet combined with the impulsive pressure generated during collapse. A parameter plot for droplets in the size range between 0.17 and 1.5 mm and laser energies between 0.2 and 4.0 mJ allows the separation of these three regimes.

PARAMETER ANALYSIS IN ACOUSTIC CONTRAST CONTROL DESIGN SCHEME FOR A LOUDSPEAKER ARRAY

2012 ◽  
Vol 20 (04) ◽  
pp. 1250016 ◽  
Author(s):  
BO-HSIEN WU ◽  
GEE-PINN TOO
Keyword(s):  
Energy Density ◽  
Potential Energy ◽  
Sound Field ◽  
Parameter Analysis ◽  
Emission Frequency ◽  
Dark Zone ◽  
Parameters Analysis ◽  
Simulation Parameters ◽  
Source Array ◽  
Audio System

The concept of acoustic contrast control divides a sound field into bright zone and dark zone. A source array is used to increase acoustic potential energy density in the bright zone and to decrease acoustic potential energy density in the dark zone by controlling amplitude and phase of each source. In the present study, a personal audio system which is based on acoustic contrast control is designed. The purpose is to focus the acoustic potential energy around the region of listener. The optimal configuration for sound field is controlled by using a loudspeaker array. Parameters analysis is considered in simulation. Parameters, such as: the quantity of loudspeakers, the spacing of loudspeakers, the length of array, and the emission frequency are discussed. Finally, two experiments are conducted in a semi-anechoic room and a reverberation room, respectively. The results are shown to verify this approach in the present study.

KTX Interior-Noise Reduction Performance Comparison Using Multichannel Active-Noise Control

2012 ◽  
Vol 152-154 ◽  
pp. 1891-1898
Author(s):  
Hyeon Seok Jang ◽  
Young Min Kim ◽  
Saehan Kim ◽  
Taeoh Lee ◽  
Kwon Soon Lee
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Noise Control ◽  
Active Noise Control ◽  
Sound Field ◽  
Performance Comparison ◽  
High Speed Rail ◽  
Active Noise ◽  
Tunnel Section ◽  
Fxlms Algorithm

In many countries, the use of the KTX high-speed rail has been generalized of late. Therefore, its customers who initially pursued only convenience and speed have begun pursuing quality services such as comfort and stability. Thus, the importance of reducing the noise in the high-speed rail is increasing. The active noise is best choice to reduce noise because of being able to actively reduce the ambient noise coming from the environmental-factor changes. But it’s too hard in a three-dimensional closed-space sound field such as the interior of a high-speed rail. In this study, we used multichannel(2x2) FXLMS algorithm for applying ANC system in KTX. In detail, after measuring the noise inside KTX during its runs in South Korea, multichannel active noise control was simulated to determine the extent to which it can reduce the noise inside KTX. Simulation was done using a multichannel FXLMS algorithm for reducing the actual noise inside KTX and the noise reduction in the open-space section of KTX was compared with that in the tunnel section, and the active-noise-control performances in the low-frequency (below 500 Hz) region were compared.

scholarly journals Extraction of sound field information from high-speed movie of flowing dust

2012 ◽  
Vol 33 (5) ◽  
pp. 316-319
Author(s):  
Mariko Akutsu ◽  
Yasuhiro Oikawa ◽  
Yoshio Yamasaki
Keyword(s):  
High Speed ◽  
Sound Field ◽  
Field Information

scholarly journals The sources of jet noise: experimental evidence

2008 ◽  
Vol 615 ◽  
pp. 253-292 ◽  
Author(s):  
CHRISTOPHER K. W. TAM ◽  
K. VISWANATHAN ◽  
K. K. AHUJA ◽  
J. PANDA
Keyword(s):  
High Speed ◽  
Noise Source ◽  
Jet Noise ◽  
Polar Angle ◽  
Sound Field ◽  
Source Distribution ◽  
Far Field ◽  
Noise Sources ◽  
Directional Information ◽  
Jet Mixing

The primary objective of this investigation is to determine experimentally the sources of jet mixing noise. In the present study, four different approaches are used. It is reasonable to assume that the characteristics of the noise sources are imprinted on their radiation fields. Under this assumption, it becomes possible to analyse the characteristics of the far-field sound and then infer back to the characteristics of the sources. The first approach is to make use of the spectral and directional information measured by a single microphone in the far field. A detailed analysis of a large collection of far-field noise data has been carried out. The purpose is to identify special characteristics that can be linked directly to those of the sources. The second approach is to measure the coherence of the sound field using two microphones. The autocorrelations and cross-correlations of these measurements offer not only valuable information on the spatial structure of the noise field in the radial and polar angle directions, but also on the sources inside the jet. The third approach involves measuring the correlation between turbulence fluctuations inside a jet and the radiated noise in the far field. This is the most direct and unambiguous way of identifying the sources of jet noise. In the fourth approach, a mirror microphone is used to measure the noise source distribution along the lengths of high-speed jets. Features and trends observed in noise source strength distributions are expected to shed light on the source mechanisms. It will be shown that all four types of data indicate clearly the existence of two distinct noise sources in jets. One source of noise is the fine-scale turbulence and the other source is the large turbulence structures of the jet flow. Some of the salient features of the sound field associated with the two noise sources are reported in this paper.

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