Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 83 for “"Sound field"”.
-
Sound field reproduction
… with the problem of reproducing a desired sound field with an array of loudspeakers. A theory based on functional analysis and the theory of<br/>integral equations is developed for the study of this problem. An attempt is made to develop a mathematical framework that can be adopted as a …
-
Quantification of the performance of 3D sound field reconstruction algorithms using high-density loudspeaker arrays and 3rd order sound field microphone measurements
… measures can be taken. The recording of the sound field, the spatialization and the development of the loudspeaker arrays are some of the greatest challenges. In this thesis, these challenges for improving immersive audio will be explored. First, there will be a short introduction about 3D …
-
Techniques of visual observation of particles in a sound field
Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1949.
-
The sound field and radiation impedance of a hyperbolic horn
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1938.
-
Performance and test-retest reliability of the digits-in-noise test used in the sound field
… would be comparable to those obtained in the sound field via various transducers. The study employed a cross-sectional, quasi-experimental research design. Fifty normal hearing participants (bilateral pure tone thresholds 0.5 – 8kHz ≤ 15dB HL) between the ages of 18 to 25 years (mean 20; SD …
-
Masking Level Differences for Speech for Normal and Hearing-Impaired Listeners Under Earphone and Sound-Field Presentation
Made available in DSpace on 2014-12-14T05:26:39Z (GMT). No. of bitstreams: 1 7607001.pdf: 3592468 bytes, checksum: 348d14872a19d54e9c73dc4ed3bd3bbf (MD5) Previous issue date: 1975
-
Psychophysical investigation of the real-ear attenuation of hearing protection devices under different sound-field diffusivity conditions
… attenuation testing specify the use of a diffuse sound field to ensure the sound field remains uniform and random-incidence in an envelope about the subject’s head (ANSI, 1974; ANSI, 1984; British BSI 5108:1983; Canadian CSA Z94.2-M1984; ISO 4869- 1:1990; Swedish SS 882151). However, there are …
-
Effects of anechoic vs. reverberant sound-field, subject gender, and outlier dismissal on the real-ear attenuation of hearing protection devices
… and three earplugs were tested in two diffuse sound fields implemented in two different sound environments with different loudspeaker configurations. In the first case, the testing environment was reverberant, with frequency-specific reverberation time characteristics as specified in ANSI …
-
Field evaluation of noise attenuation and comfort performance of earplug, earmuff, and ear canal cap hearing protectors under the ANSI S12.6- 1984 sound field standard
A field research study was conducted to determine the actual noise attenuation and perceived comfort achieved by 40 noise-exposed industrial workers in 5 industrial workplaces wearing 4 different industrial hearing protection devices (HPDs) while on the job. Over 2 consecutive 3-week periods of HPD …
-
Efficient modeling of sound source radiation in free-space and room environments
… environment, and (2) the prediction of the sound field in a room environment based on that free-space information.</p> <p>To achieve a high modeling efficiency, i.e., to reduce the number of modeling parameters while still maintaining acceptable accuracy, a Multipole Equivalent Source Model …
-
Propagation Of Sound In The Vicinity Of Rigid Porous Interfaces
<p>Propagation of sound in the vicinity of rigid porous interfaces is investigated systematically to facilitate the acoustical characterization of sound absorption materials for noise reduction applications. Various rigid porous interfaces are considered: (1) a semi-infinite porous layer; (2) a …
-
Analytical investigation of active control of radiated inlet noise from turbofan engines
… the duct to destructively interfere with the sound field generated by the fan. The development of the analytical expressions of the radiated sound fields due to both the fan disturbance and the control sources is based on duct modal expansion. Numerical analyses are presented for different …
-
Three-dimensional strong acousto-optic interaction theory
… the interaction between light and "strong" sound fields. Strong refers to a sound field strength sufficient to deflect most of the incident light into the first diffracted order, but not strong enough to induce nonlinear behavior in the acousto-optic cell. Primary emphasis is placed on …
-
Active control of sound transmission through plates in a reverberant environment
Active control of sound transmission through an elastic plate placed between two reverberation chambers is studied experimentally. Active acoustic control is performed using piezoelectric sensors and actuators bonded to the plate. The control technique uses an adaptive control algorithm. Results …
-
Implementing and testing a panel-based method for modeling acoustic scattering from CFD input
… need to model both the direct and the scattered sound field in order to determine the resultant spectrum and levels. While the direct sound field may be obtained using CFD plus surface integral methods such as the Ffowcs-Williams Hawkings method, the scattered sound field is complicated by its …
-
A study of active control techniques for noise reduction in an aircraft fuselage model
… the elementary mechanisms of control of sound transmission into aircraft cabins by two active control techniques: propeller synchrophasing and active vibration control. Propeller synchrophasing involves controlling the relative rotational phase of the engines to achieve maximum cabin …
-
Rotor Inflow Noise Caused by a Boundary Layer: Inflow Measurements and Noise Predictions
… correlation function was used to predict the far-field radiated noise from the rotor at various operating and flow conditions. Predictions show the sound field is dominated by the effects of "haystacking" which is further increased with the inclusion of the presence of the wall. Directivity …
-
The active minimisation of harmonic enclosed sound fields, with particular application to propeller induced cabin noise
… of noise levels in harmonically excited enclosed sound fields. This possibility is studied initially through the use of an analytical model of a single frequency 'two-dimensional' rectangular, enclosed sound field of low modal density. Quadratic optimisation theory is used to predict the …
-
Laser Doppler Vibrometry Based Remote Sensing for Active Noise Control
… in the published literature in the context of sound/noise measurement and control. This thesis, therefore, investigates and develops LDV-based remote acoustic sensing techniques for ANC applications, particularly ANC headrests and windows. The first part of the thesis studies how to use an LDV …
Page 1 of 5