Proximity effect (audio)

About: Proximity effect (audio) is a research topic. Over the lifetime, 839 publications have been published within this topic receiving 8582 citations.

The Pressure Distribution in the Auditory Canal in a Progressive Sound Field

Abstract: The variation of the sound pressure along the auditory canal was determined experimentally on a number of subjects, male and female, placed in a progressive sound field This was accomplished by insertion of a small flexible probe microphone at various positions along the auditory canal The subjects were placed in front of a loudspeaker in a room free from acoustic wall reflections The free sound field at the subjects' location was essentially that of a plane progressive wave The measurements were carried out over the significant range of audiofrequencies for various orientations in azimuth of the subjects with respect to the sound source The sound pressure at the eardrum is found to be greater than the free‐field pressure The average ratio of these two quantities is a function of frequency, and reaches values of about 20 db in the vicinity of 3000 cps The human ear is thus an effective acoustic “amplifier” The increase in sound pressure at the eardrum over the free‐field pressure is caused by a combination effect of diffraction by the head and pinna and resonance in the auditory canal The measurements of the sound pressures at several other positions along the auditory canal serve to separate these two phenomena to a certain extent and to furnish additional information about the pressure distribution Most of the data were obtained with a group of male subjects, but measurements on a few women did not show any marked discrepancies

A Simple Synthesis Method for Solving the Elements of Well-Detached Eclipsing Systems

Abstract: A simple synthesis method for analyzing the light curves of detached eclipsing binaries exhibiting only small oblateness is outlined. The resulting computer program is flexible to use and faster than D.B. Wood’s widely-used program WINK, which was designed for systems with moderately distorted components. The basic indeterminacies of light curve solutions are mentioned.

Microphone having linear optical transducers

Abstract: Microphone having linear optical transducers. The present invention includes the use of linear optical transducers in several configurations to detect the motion of one or more conventional microphone diaphragms in proportional response to incident acoustic signals. A light source, such as a laser or a light emitting diode directs light onto a reflecting microphone diaphragm responsive to sound waves, and the position of the reflected light is monitored using a position sensitive detector which effectively eliminates effects of light source intensity on the optical transducer-processed signal. Other embodiments make use of either a fixed knife edge or a knife edge which moves in response to the motion of the diaphragm to interrupt the light source in a proportional manner to the amplitude of motion of the diaphragm.

Fully developed triplet proximity effect.

Abstract: We present a model for the fully developed proximity effect in superconductor-ferromagnet heterostructures. Within the circuit-theory approximation, we evaluate the Green functions, the density of states, and the Josephson current which depend essentially on the magnetic configuration.

A low-noise differential microphone inspired by the ears of the parasitoid fly Ormia ochracea

Abstract: A miniature differential microphone is described having a low-noise floor. The sensitivity of a differential microphone suffers as the distance between the two pressure sensing locations decreases, resulting in an increase in the input sound pressure-referred noise floor. In the microphone described here, both the diaphragm thermal noise and the electronic noise are minimized by a combination of novel diaphragm design and the use of low-noise optical sensing that has been integrated into the microphone package. The differential microphone diaphragm measures 1 x 2 mm(2) and is fabricated out of polycrystalline silicon. The diaphragm design is based on the coupled directionally sensitive ears of the fly Ormia ochracea. The sound pressure input-referred noise floor of this miniature differential microphone has been measured to be less than 36 dBA.