New method for sound field reproduction

1989 ◽  
Vol 35 (4) ◽  
pp. 775-784 ◽  
Author(s):  
M. Takemoto ◽  
S. Yakko ◽  
N. Kuroda ◽  
S. Sano ◽  
T. Miyachi ◽  
...  
Keyword(s):  
Sound Field ◽  
New Method

A new method of estimating acoustic intensity applied to the sound field near a military jet aircraft

2014 ◽  
Vol 136 (4) ◽  
pp. 2081-2081
Author(s):  
Trevor A. Stout ◽  
Kent L. Gee ◽  
Tracianne B. Neilsen ◽  
Derek C. Thomas ◽  
Benjamin Y. Christensen ◽  
...  
Keyword(s):  
Sound Field ◽  
New Method ◽  
Acoustic Intensity

A Tangibly Reinforced Speech Reception Threshold Procedure for Use with Small Children

1976 ◽  
Vol 41 (3) ◽  
pp. 333-338
Author(s):  
Frederick N. Martin ◽  
Sherry Coombes
Keyword(s):  
Operant Conditioning ◽  
Sound Field ◽  
Normal Hearing ◽  
New Method ◽  
Small Children ◽  
Field System ◽  
Speech Reception ◽  
Threshold Procedure ◽  
Speech Reception Thresholds ◽  
Hearing Children

Forty normal-hearing children between 17 and 56 months were tested using a new method for determining speech reception thresholds. The words employed were names for parts of a device that was in the form of a colorful clown. The device automatically rewarded the child with a small piece of candy each time he pressed the part of the clown that had been announced through the sound field system of a speech audiometer. Results showed that operant conditioning speech audiometry using tangible reinforcers is feasible for small children. Both boys and girls can be tested accurately by this method down to age two and one-half years.

SIMULATION OF ACTIVE NOISE CONTROL IN ENCLOSURES USING DIRECT SOUND FIELD PREDICTION

2009 ◽  
Vol 17 (01) ◽  
pp. 83-107 ◽  
Author(s):  
CHRISTOPHER G. PROVATIDIS ◽  
SPIRIDON T. MOUZAKITIS ◽  
GEORGE N. CHARALAMPOPOULOS
Keyword(s):  
Boundary Conditions ◽  
Noise Control ◽  
Active Noise Control ◽  
Sound Field ◽  
New Method ◽  
Test Case ◽  
Sensors And Actuators ◽  
Sound Fields ◽  
Secondary Sources ◽  
Active Noise

This paper is concerned with the active control of sound fields in enclosures. Specifically, the numerical problem of determining the optimum locations of control sensors and actuators is addressed. A new method for determining the optimum secondary sources strength is proposed, based on the explicit prediction of the sound field, which makes the simulation of realistic acoustical applications feasible, in terms of the enclosure's boundary conditions. The irregular geometry of a car cabin with complex boundary conditions is used in order to demonstrate the application of the new method to a test case where the existing methods cannot theoretically apply without resolving to significant numerical error. The new method of determining the secondary sources strength is combined with a modified genetic and a gradient optimization algorithm so as to locate the optimum positions of active noise control transducers for global sound field control. The overall algorithm, constituting of the method for calculating the secondary sources' strength and the optimization algorithms, is adjusted with computational improvements for better performance.

ENHANCED RAY THEORY

2001 ◽  
Vol 09 (01) ◽  
pp. 169-182 ◽  
Author(s):  
NICK MALTSEV
Keyword(s):  
Sound Speed ◽  
Sound Field ◽  
New Method ◽  
Analytic Approximation ◽  
Theory Approach ◽  
Field Calculation ◽  
Ray Theory ◽  
Method Of Calculation

The numerical problems of SWAM'99 workshop are quite challenging for any method of sound field calculation. This report presents a detailed description of the enhanced ray theory approach briefly outlined in Ref. 2. It contains a new method of phase and amplitude computation along the ray, a new method of calculation of eigenrays, and a new method of analytic approximation of sound-speed and density. An application of these methods is presented.

Selective Sampling and Orientation of Non-Homogeneous Tissues

1968 ◽  
Vol 26 ◽  
pp. 98-99
Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Random Sampling ◽  
New Method ◽  
Microscope Examination ◽  
Small Areas ◽  
Selective Sampling ◽  
Large Numbers ◽  
Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

Decay of Temporary Threshold Shift in Noise

1973 ◽  
Vol 16 (2) ◽  
pp. 267-270 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo ◽  
Gloria S. Gordon
Keyword(s):  
Sound Field ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise ◽  
Lower Asymptote

Groups of monaural chinchillas trained in behavioral audiometry were exposed in a diffuse sound field to an octave-band noise centered at 4.0 k Hz. The growth of temporary threshold shift (TTS) at 5.7 k Hz from zero to an asymptote (TTS ∞ ) required about 24 hours, and the growth of TTS at 5.7 k Hz from an asymptote to a higher asymptote, about 12–24 hours. TTS ∞ can be described by the equation TTS ∞ = 1.6(SPL-A) where A = 47. These results are consistent with those previously reported in this journal by Carder and Miller and Mills and Talo. Whereas the decay of TTS ∞ to zero required about three days, the decay of TTS ∞ to a lower TTS ∞ required about three to seven days. The decay of TTS ∞ in noise, therefore, appears to require slightly more time than the decay of TTS ∞ in the quiet. However, for a given level of noise, the magnitude of TTS ∞ is the same regardless of whether the TTS asymptote is approached from zero, from a lower asymptote, or from a higher asymptote.

Modified Earpieces and CROS for High Frequency Hearing Losses

1968 ◽  
Vol 11 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Elizabeth Dodds ◽  
Earl Harford
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Sound Field ◽  
Intensity Level ◽  
Test Results ◽  
High Frequency Hearing Loss ◽  
Increased Sensitivity ◽  
Difficult Cases

Persons with a high frequency hearing loss are difficult cases for whom to find suitable amplification. We have experienced some success with this problem in our Hearing Clinics using a specially designed earmold with a hearing aid. Thirty-five cases with high frequency hearing losses were selected from our clinical files for analysis of test results using standard, vented, and open earpieces. A statistical analysis of test results revealed that PB scores in sound field, using an average conversational intensity level (70 dB SPL), were enhanced when utilizing any one of the three earmolds. This result was due undoubtedly to increased sensitivity provided by the hearing aid. Only the open earmold used with a CROS hearing aid resulted in a significant improvement in discrimination when compared with the group’s unaided PB score under earphones or when comparing inter-earmold scores. These findings suggest that the inclusion of the open earmold with a CROS aid in the audiologist’s armamentarium should increase his flexibility in selecting hearing aids for persons with a high frequency hearing loss.

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