The relative contribution of onset asynchrony, harmonic ratios and angular separation of sound sources to the cross‐spectral grouping of complex tones in a free field

1999 ◽  
Vol 106 (4) ◽  
pp. 2238-2238
Author(s):  
Martine Turgeon ◽  
Albert S. Bregman
Keyword(s):  
Free Field ◽  
Angular Separation ◽  
Sound Sources ◽  
Relative Contribution ◽  
Complex Tones ◽  
The Cross ◽  
Onset Asynchrony

Newborn Infants Detect Cues of Concurrent Sound Segregation

2015 ◽  
Vol 37 (2) ◽  
pp. 172-181 ◽  
Author(s):  
Alexandra Bendixen ◽  
Gábor P. Háden ◽  
Renáta Németh ◽  
Dávid Farkas ◽  
Miklós Török ◽  
...  
Keyword(s):  
Newborn Infants ◽  
Random Order ◽  
Event Related Potential ◽  
Physical Parameters ◽  
Veridical Perception ◽  
Sound Sources ◽  
Perceptual Object ◽  
Delayed Onset ◽  
Sound Segregation ◽  
Complex Tones

Separating concurrent sounds is fundamental for a veridical perception of one's auditory surroundings. Sound components that are harmonically related and start at the same time are usually grouped into a common perceptual object, whereas components that are not in harmonic relation or have different onset times are more likely to be perceived in terms of separate objects. Here we tested whether neonates are able to pick up the cues supporting this sound organization principle. We presented newborn infants with a series of complex tones with their harmonics in tune (creating the percept of a unitary sound object) and with manipulated variants, which gave the impression of two concurrently active sound sources. The manipulated variant had either one mistuned partial (single-cue condition) or the onset of this mistuned partial was also delayed (double-cue condition). Tuned and manipulated sounds were presented in random order with equal probabilities. Recording the neonates' electroencephalographic responses allowed us to evaluate their processing of the sounds. Results show that, in both conditions, mistuned sounds elicited a negative displacement of the event-related potential (ERP) relative to tuned sounds from 360 to 400 ms after sound onset. The mistuning-related ERP component resembles the object-related negativity (ORN) component in adults, which is associated with concurrent sound segregation. Delayed onset additionally led to a negative displacement from 160 to 200 ms, which was probably more related to the physical parameters of the sounds than to their perceptual segregation. The elicitation of an ORN-like response in newborn infants suggests that neonates possess the basic capabilities of segregating concurrent sounds by detecting inharmonic relations between the co-occurring sounds.

scholarly journals CROSS SECTION ASYMMETRY OF THE 12C(γ,p0)11B AND 12C(γ,p1)11B REACTIONS AT PHOTON ENERGIES 40...55MeV

2019 ◽  
pp. 26-37
Author(s):  
D.D. Burdeinyi ◽  
J. Brudvik ◽  
V.B. Ganenko ◽  
K. Hansen ◽  
K. Fissum ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Energy Range ◽  
Cross Section ◽  
Relative Contribution ◽  
Linearly Polarized ◽  
The Asymmetry ◽  
The Cross ◽  
Tagged Photons

The asymmetry of the cross section of the 12C(γ,p0)11B and 12C(γ,p1)11B reactions has been measured in the energy range 40...55MeV using linearly polarized tagged photons of the MAX-lab facility. The asymmetry of the process 12C(⃗γ,p0)11B is Σ ≈ 0.85, that implies one-particle reaction mechanism. The asymmetry of the reaction 12C(⃗γ,p1)11B is smaller, Σ ≈ 0.6...0.7, that may be due to the stronger relative contribution of the 2h−1p mechanism to the dominant one-particle reaction mechanism.

scholarly journals Disentangling interstellar plasma screens with pulsar VLBI: combining auto- and cross-correlations

2019 ◽  
Vol 488 (4) ◽  
pp. 4963-4971 ◽  
Author(s):  
D Simard ◽  
U-L Pen ◽  
V R Marthi ◽  
W Brisken
Keyword(s):  
Angular Position ◽  
Angular Separation ◽  
Pulsar Emission ◽  
Scattering Geometry ◽  
Interstellar Plasma ◽  
Single Station ◽  
Cross Correlations ◽  
The Mean ◽  
The Cross ◽  
Scattering Systems

Abstract Current methods of measuring distances to pulsar scattering screens rely on a single screen dominating the scintillation pattern. We present a novel technique to reconstruct the scattered flux of a pulsar and solve for the scattering geometry in cases where the scattering environment along the line of sight to the pulsar is complex and may be composed of multiple scattering screens. This technique combines interferometric visibilities with cross-correlations of single-station intensities. It takes advantage of the fact that if one considers the interference of radiation from two points in the scattered image in delay–delay rate space, the visibilities are sensitive to the mean angular position of the points, while the cross-correlated intensities are sensitive to their angular separation. By combining the visibilities and the cross-correlated intensities, it is possible to measure the angular locations of both points in the pair. We show that this technique is able to reconstruct the published scattering geometry of PSR B0834+06. We then apply this technique to one-dimensional simulations of more complicated scattering systems, where we find that it can distinguish features from different scattering screens. This technique holds promise for studies of the interstellar medium and pulsars themselves: It will allow the application of scintillometry techniques, such as resolving pulsar emission regions using interstellar scattering, to sources for which a current lack of understanding of the scattering environment has precluded their use.

Spatial acuity of ultrasound hearing in flying crickets.

1997 ◽  
Vol 200 (14) ◽  
pp. 1999-2006 ◽  
Author(s):  
R A Wyttenbach ◽  
R R Hoy
Keyword(s):  
Escape Response ◽  
Angular Separation ◽  
Sound Sources ◽  
Original Source ◽  
Teleogryllus Oceanicus ◽  
Test Pulse ◽  
Spatial Acuity ◽  
Test Discrimination

The minimum audible angle is the smallest angular separation at which two sounds are perceived as coming from distinct sources. To determine the spatial acuity of hearing in crickets, we measured minimum audible angles at various locations in azimuth and elevation. Crickets (Teleogryllus oceanicus) were able to discriminate between sources separated by 11.25 degrees (1/32 of a circle) in azimuth directly ahead of them; acuity declined to 45 degrees in azimuth for sound sources 90 degrees to the side and then improved to 33.75 degrees at the rear. Crickets were also able to discriminate between sources separated in elevation, although acuity was much poorer, ranging from 45 degrees at the front and rear of the animal to 90 degrees below the animal. A habituation-dishabituation test was used to test discrimination. This involved presenting a train of ultrasound pulses from one location, habituating the cricket's escape response. This train was followed by a test pulse of ultrasound from another location, after which a final pulse was presented from the original source. If the test pulse was discriminated from the habituating pulses, then the response to the final pulse was dishabituated. To determine the minimum audible angle, we repeated such tests while moving the two sound sources closer together until dishabituation no longer occurred.

Masking in Three-Dimensional Auditory Displays

1992 ◽  
Vol 34 (3) ◽  
pp. 255-265 ◽  
Author(s):  
Theodore J. Doll ◽  
Thomas E. Hanna ◽  
Joseph S. Russotti
Keyword(s):  
Head Movement ◽  
Signal To Noise Ratio ◽  
Free Field ◽  
Three Dimensional ◽  
Angular Separation ◽  
Broadband Noise ◽  
Auditory Display ◽  
Signal To Noise ◽  
Correlated Sources ◽  
Auditory Displays

The extent to which simultaneous inputs in a three-dimensional (3D) auditory display mask one another was studied in a simulated sonar task. The minimum signal-to-noise ratio (SNR) required to detect an amplitude-modulated SOO-Hz tone in a background of broadband noise was measured using a loudspeaker array in a free field. Three aspects of the 3D array were varied: angular separation of the sources, degree of correlation of the background noises, and listener head movement. Masking was substantially reduced when the sources were uncorrelated. The SNR needed for detection decreased with source separation, and the rate of decrease was significantly greater with uncorrelated sources than with partially or fully correlated sources. Head movement had no effect on the SNR required for detection. Implications for the design and application of 3D auditory displays are discussed.

CME Expansion as Revealed by Joint Measurements by STEREO, Wind, MESSENGER and Venus Express

2020 ◽  
Author(s):  
Noé Lugaz ◽  
Tarik Salman ◽  
Réka Winslow ◽  
Nada Al-Haddad ◽  
Charles Farrugia ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Free Field ◽  
Radial Distance ◽  
Angular Separation ◽  
Local Measurements ◽  
Two Measures ◽  
Plasma Measurements ◽  
The Magnetic Field ◽  
Force Free Field

<p>The radial expansion of magnetic ejecta (ME) has been investigated through the analysis of remote observations, the variation of their properties with radial distance and from local in situ plasma measurements showing a decreasing speed profile, as first discussed almost 40 years ago. However, little is known on how local measurements compare to global measurements of expansion and what causes the different expansion properties of different CMEs. In order to correctly forecast CME properties at Earth from measurements below 0.9 AU CME expansion must be considered, and first, understood.  Here, we take advantage of 42 CMEs being measured by two spacecraft in radial conjunction to determine how the magnetic field decrease with distance, as a measure of their global expansion. As all these CMEs are also measured near 1 AU by STEREO or Wind, we are able to determine their local expansion from the speed decrease. We find that these two measures have little relation with each other, even when looking only at the events with the closest conjunctions (in term of angular separation). We also determine the relation between measures of the CME expansion and the CME properties. Lastly, we also determine the evolution of the ME radial, azimuthal and north-south magnetic field with distance, which allow us to compare their evolution with the expectations from force-free field configurations.</p>

Reproduction of Phantom Sources Improves with Separation of Direct and Reflected Sounds

2015 ◽  
Vol 40 (4) ◽  
pp. 575-584
Author(s):  
Piotr Kleczkowski ◽  
Aleksandra Król ◽  
Paweł Małecki
Keyword(s):  
Sound Source ◽  
Sound Field ◽  
Angular Separation ◽  
Impulse Responses ◽  
Sound Sources ◽  
Perceptual Effect ◽  
Multichannel Systems ◽  
Virtual Acoustics

AbstractIn virtual acoustics or artificial reverberation, impulse responses can be split so that direct and reflected components of the sound field are reproduced via separate loudspeakers. The authors had investigated the perceptual effect of angular separation of those components in commonly used 5.0 and 7.0 multichannel systems, with one and three sound sources respectively (Kleczkowski et al., 2015, J. Audio Eng. Soc. 63, 428-443). In that work, each of the front channels of the 7.0 system was fed with only one sound source. In this work a similar experiment is reported, but with phantom sound sources between the front loud- speakers. The perceptual advantage of separation was found to be more consistent than in the condition of discrete sound sources. The results were analysed both for pooled listeners and in three groups, according to experience. The advantage of separation was the highest in the group of experienced listeners.

Functional generalized inverse beamforming with regularization matrix applied to sound source localization

2016 ◽  
Vol 23 (18) ◽  
pp. 2977-2988 ◽  
Author(s):  
Shu Li ◽  
Zhongming Xu ◽  
Zhifei Zhang ◽  
Yansong He ◽  
Jin Mao
Keyword(s):  
Source Localization ◽  
Dynamic Range ◽  
Generalized Inverse ◽  
Free Field ◽  
Computation Time ◽  
Side Lobe ◽  
Sound Sources ◽  
Low Frequencies ◽  
Common Application ◽  
Regularization Matrix

Microphone arrays have become a popular technique to identify sound sources. They can be utilized to localize the sources for various applications. The most common application is the conventional beamforming that provides the source maps with strong side lobes and poor spatial resolution at low frequencies. To overcome these problems, the focus is set on deconvolution and generalized inverse techniques such as a deconvolution approach for the mapping of acoustic sources (DAMAS) and generalized inverse beamforming (GIB). Although the source maps are clearly improved, these methods have the shortcomings of expensive computing and limited dynamic range. In this paper, we propose a source localization method called functional generalized inverse beamforming with regularization matrix (FGIBR) based on an inverse problem. Compared with GIB, the accuracy of FGIBR could be improved by introducing a new beamforming regularization matrix and a scaling parameter c0. Also the dynamic range of the source maps can be increased by applying FGIBR with an exponent parameter called order v. Several simulated examples are given to illustrate that the side lobes are suppressed and the main lobe becomes much narrow; moreover, if order v is increased, the beamforming side lobes can be sharply reduced and the actual position of the noise source can be precisely located. Then FGIBR is implemented to deal with experimental data in the free field. In the case of the experiment, the source is correctly located. The proposed FGIBR demonstrates a good performance in terms of resolution and side lobe rejection compared with other beamforming methods. Furthermore, the computation time is shown to be low if the iteration and order are reasonable.

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