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Binaural Unmasking
Binaural unmasking is phenomenon of auditory perception discovered by Ira Hirsh. In binaural unmasking, the brain combines information from the two ears in order to improve signal detection and identification in noise. The phenomenon is most commonly observed when there is a difference between the interaural phase of the signal and the interaural phase of the noise. When such a difference is present there is an improvement in masking threshold compared to a reference situation in which the interaural phases are the same, or when the stimulus has been presented monaurally. Those two cases usually give very similar thresholds. The size of the improvement is known as the "binaural masking level difference" (BMLD), or simply as the "masking level difference". Binaural unmasking is most effective at low frequencies. The BMLD for pure tones in broadband noise reaches a maximum value of about 15 decibels (dB) at 250 Hz and progressively declines to 2-3 dB at 1500 Hz. The BM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ira Hirsh
Ira Hirsh (February 22, 1922 – January 12, 2010) was an American psychologist who made early contributions to the field of audiology. He was the Edward Mallinckrodt Distinguished University Professor of Psychology and Audiology at Washington University in St. Louis (WashU) and served as president of the Acoustical Society of America. Biography Born in New York, Hirsh earned an undergraduate degree from the New York State College for Teachers. While earning a master's degree at the Northwestern University School of Communication, he worked for a CBS Radio station in Chicago as a staff announcer and radio drama actor. After serving in the United States Army Air Forces, Hirsh earned a Ph.D. at Harvard University, where he conducted research at the Psycho-Acoustics Laboratory (PAL) under Stanley Smith Stevens. He took a position at the PAL before joining the Central Institute for the Deaf (a school for the deaf that teaches students using listening and spoken language which is affilia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise
Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arises when the brain receives and perceives a sound. Acoustic noise is any sound in the acoustic domain, either deliberate (e.g., music or speech) or unintended. In contrast, noise in electronics may not be audible to the human ear and may require instruments for detection. In audio engineering, noise can refer to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as a hiss. This signal noise is commonly measured using A-weighting or ITU-R 468 weighting. In experimental sciences, noise can refer to any random fluctuations of data that hinders perception of a signal. Measurement Sound is measured based on the amplitude and frequency of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Masking Threshold
Masking threshold within acoustics (a branch of physics that deals with topics such as vibration, sound, ultrasound, and infrasound), refers to a process where if there are two concurrent sounds and one sound is louder than the other, a person may be unable to hear the soft sound because it is masked by the louder sound. So the masking threshold is the sound pressure level of a sound needed to make the sound audible in the presence of another noise called a "masker". This threshold depends upon the frequency, the type of masker, and the kind of sound being masked. The effect is strongest between two sounds close in frequency. In the context of audio transmission, there are some advantages to being unable to perceive a sound. In audio encoding, for example, better compression can be achieved by omitting the inaudible tones. This requires fewer bits to encode the sound and reduces the size of the final file. Applications in audio compression It is uncommon to work with only one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decibels
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 101/10 (approximately ) or root-power ratio of 101/20 (approximately ). The strict original usage above only expresses a relative change. However, the word decibel has since also been used for expressing an absolute value that is relative to some fixed reference value, in which case the dB symbol is often suffixed with letter codes that indicate the reference value. For example, for the reference value of 1 volt, a common suffix is " V" (e.g., "20 dBV"). As it originated from a need to express power ratios, two principal types of scaling of the decibel are used to provide consistency depending on whether the scaling refers to ratios of power quantities or root-power quantities. When expressing a power ratio, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speech
Speech is the use of the human voice as a medium for language. Spoken language combines vowel and consonant sounds to form units of meaning like words, which belong to a language's lexicon. There are many different intentional speech acts, such as informing, declaring, asking, persuading, directing; acts may vary in various aspects like enunciation, Intonation (linguistics), intonation, loudness, and Speech tempo, tempo to convey meaning. Individuals may also unintentionally communicate aspects of their social position through speech, such as sex, age, place of origin, physiological and mental condition, education, and experiences. While normally used to facilitate communication with others, people may also use speech without the intent to communicate. Speech may nevertheless express emotions or desires; people Talking to oneself, talk to themselves sometimes in acts that are a development of what some psychologists (e.g., Lev Vygotsky) have maintained is the use of silent spee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interaural Time Difference
The interaural time difference (or ITD) when concerning humans or animals, is the difference in arrival time of a sound between two ears. It is important in the Sound localization, localization of sounds, as it provides a cue to the direction or angle of the sound source from the head. If a signal arrives at the head from one side, the signal has further to travel to reach the far ear than the near ear. This pathlength difference results in a time difference between the sound's arrivals at the ears, which is detected and aids the process of identifying the direction of sound source. When a signal is produced in the horizontal plane, its angle in relation to the head is referred to as its azimuth, with 0 degrees (0°) azimuth being directly in front of the listener, 90° to the right, and 180° being directly behind. Different methods for measuring ITDs * For an abrupt stimulus such as a click, onset ITDs are measured. An onset ITD is the time difference between the onset of the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cocktail Party Effect
The cocktail party effect refers to a phenomenon wherein the brain focuses a person's attention on a particular stimulus, usually Auditory system, auditory. This focus excludes a range of other stimuli from conscious awareness, as when a partygoer follows a single conversation in a noisy room. This ability is widely distributed among humans, with most listeners more or less easily able to portion the totality of sound detected by the ears into distinct streams, and subsequently to decide which streams are most pertinent, excluding all or most others. It has been proposed that a person's sensory memory subconsciously parses all stimuli and identifies discrete portions of these sensations according to their Salience (neuroscience), salience. This allows most people to tune effortlessly into a single voice while tuning out all others. The phenomenon is often described as a "selective attention" or "selective hearing". It may also describe a similar phenomenon that occurs when one may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radian
The radian, denoted by the symbol rad, is the unit of angle in the International System of Units (SI) and is the standard unit of angular measure used in many areas of mathematics. It is defined such that one radian is the angle subtended at the centre of a circle by an Circular arc, arc that is equal in length to the radius. The unit was formerly an SI supplementary unit and is currently a dimensionless unit, dimensionless SI derived unit,: "The CGPM decided to interpret the supplementary units in the SI, namely the radian and the steradian, as dimensionless derived units." defined in the SI as 1 rad = 1 and expressed in terms of the SI base unit metre (m) as . Angles without explicitly specified units are generally assumed to be measured in radians, especially in mathematical writing. Definition One radian is defined as the angle at the center of a circle in a plane that wikt:subtend, subtends an arc whose length equals the radius of the circle. More generally, the magnit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lloyd A
Lloyd, Lloyd's, or Lloyds may refer to: People * Lloyd (name), a variation of the Welsh word ' ("grey") or ' ** List of people with given name Lloyd ** List of people with surname Lloyd * Lloyd (singer) (born 1986), American singer Places United States * Lloyd, Florida * Lloyd, Kentucky * Lloyd, Montana * Lloyd, New York * Lloyd, Ohio * Lloyds, Alabama * Lloyds, Maryland * Lloyds, Virginia Elsewhere * Lloydminster, or "Lloyd", straddling the provincial border between Alberta and Saskatchewan, Canada Companies and businesses Derived from Lloyd's Coffee House * Lloyd's Coffee House, a London meeting place for merchants and shipowners between about 1688 and 1774 * Lloyd's of London, a British insurance market ** ''Lloyd's of London'' (film), a 1936 film about the insurance market ** Lloyd's building, its headquarters ** Lloyd's Agency Network * '' Lloyd's List'', a website and 275-year-old daily newspaper on shipping and global trade ** '' Lloyd's List Intellige ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Comparative And Physiological Psychology
The ''Journal of Comparative and Physiological Psychology'' was a peer-reviewed academic journal published by the American Psychological Association. It was established in 1921 as the result of a merger between two journals, ''Psychobiology'' (1918–1920) and the ''Journal of Animal Behavior'' (1911–1916), under the title ''Journal of Comparative Psychology''. It was renamed ''Journal of Comparative and Physiological Psychology'' in 1947. Publication ceased in 1982 when the journal was split into ''Behavioral Neuroscience'' and the re-instated ''Journal of Comparative Psychology''.Dewsbury, Donald A. (June 2012)Historical trends in American comparative psychology.''The Behavioral Neuroscientist and Comparative Psychologist'' From 1965 till 1982, the journal was abstracted and indexed in Index Medicus/MEDLINE/PubMed PubMed is an openly accessible, free database which includes primarily the MEDLINE database of references and abstracts on life sciences and biomedical topi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Localization
Sound localization is a listener's ability to identify the location or origin of a detected sound in direction and distance. The sound localization mechanisms of the mammalian auditory system have been extensively studied. The auditory system uses several cues for sound source localization, including time difference and level difference (or intensity difference) between the ears, and spectral information. Other animals, such as birds and reptiles, also use them but they may use them differently, and some also have localization cues which are absent in the human auditory system, such as the effects of ear movements. Animals with the ability to localize sound have a clear evolutionary advantage. How sound reaches the brain Sound is the perceptual result of mechanical vibrations traveling through a medium such as air or water. Through the mechanisms of compression and rarefaction, sound waves travel through the air, bounce off the Pinna (anatomy), pinna and concha of the exter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Action Potential
An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific Cell (biology), cell rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of Membrane potential#Cell excitability, excitable cells, which include animal cells like neurons and myocyte, muscle cells, as well as some plant cells. Certain endocrine cells such as pancreatic beta cells, and certain cells of the anterior pituitary gland are also excitable cells. In neurons, action potentials play a central role in cell–cell interaction, cell–cell communication by providing for—or with regard to saltatory conduction, assisting—the propagation of signals along the neuron's axon toward axon terminal, synaptic boutons situated at the ends of an axon; these signals can then connect wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
