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Reverberation Level
Reverberation (also known as reverb), in acoustics, is a persistence of sound, after a sound is produced. Reverberation is created when a sound or signal is reflected causing numerous reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space – which could include furniture, people, and air. This is most noticeable when the sound source stops but the reflections continue, their amplitude decreasing, until zero is reached. Reverberation is frequency dependent: the length of the decay, or reverberation time, receives special consideration in the architectural design of spaces which need to have specific reverberation times to achieve optimum performance for their intended activity. In comparison to a distinct echo, that is detectable at a minimum of 50 to 100 ms after the previous sound, reverberation is the occurrence of reflections that arrive in a sequence of less than approximately 50 ms. As time passes, the amplitude of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Chord With Reverb
C, or c, is the third letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''cee'' (pronounced ), plural ''cees''. History "C" comes from the same letter as "G". The Semites named it gimel. The sign is possibly adapted from an Egyptian hieroglyph for a staff sling, which may have been the meaning of the name ''gimel''. Another possibility is that it depicted a camel, the Semitic name for which was ''gamal''. Barry B. Powell, a specialist in the history of writing, states "It is hard to imagine how gimel = "camel" can be derived from the picture of a camel (it may show his hump, or his head and neck!)". In the Etruscan language, plosive consonants had no contrastive voicing, so the Greek ' Γ' (Gamma) was adopted into the Etruscan alphabet to represent . Already in the Western Greek alphabet, Gamma first took a '' form in Early Etruscan, then '' in Classical Et ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stopwatch
A stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation. A large digital version of a stopwatch designed for viewing at a distance, as in a sports stadium, is called a stop clock. In manual timing, the clock is started and stopped by a person pressing a button. In fully automatic time, both starting and stopping are triggered automatically, by sensors. The timing functions are traditionally controlled by two buttons on the case. Pressing the top button starts the timer running, and pressing the button a second time stops it, leaving the elapsed time displayed. A press of the second button then resets the stopwatch to zero. The second button is also used to record ''split times'' or ''lap times''. When the split time button is pressed while the watch is running it allows the elapsed time to that point to be read, but the watch mechanism continues running to record total elapsed time. Pressing the split button a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empirical
Empirical evidence for a proposition is evidence, i.e. what supports or counters this proposition, that is constituted by or accessible to sense experience or experimental procedure. Empirical evidence is of central importance to the sciences and plays a role in various other fields, like epistemology and law. There is no general agreement on how the terms ''evidence'' and ''empirical'' are to be defined. Often different fields work with quite different conceptions. In epistemology, evidence is what justifies beliefs or what determines whether holding a certain belief is rational. This is only possible if the evidence is possessed by the person, which has prompted various epistemologists to conceive evidence as private mental states like experiences or other beliefs. In philosophy of science, on the other hand, evidence is understood as that which ''Scientific method#Confirmation, confirms'' or ''disconfirms'' Hypothesis#Scientific hypothesis, scientific hypotheses and arbitrates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manfred R
''Manfred: A dramatic poem'' is a closet drama written in 1816–1817 by Lord Byron. It contains supernatural elements, in keeping with the popularity of the ghost story in England at the time. It is a typical example of a Gothic fiction. Byron commenced this work in late 1816, a few months after the famous ghost-story sessions with Percy Bysshe Shelley and Mary Shelley that provided the initial impetus for '' Frankenstein; or, The Modern Prometheus ''. The supernatural references are made clear throughout the poem. ''Manfred'' was adapted musically by Robert Schumann in 1852, in a composition entitled '' Manfred: Dramatic Poem with Music in Three Parts'', and in 1885 by Pyotr Ilyich Tchaikovsky in his ''Manfred Symphony''. Friedrich Nietzsche was inspired by the poem's depiction of a super-human being to compose a piano score in 1872 based on it, "Manfred Meditation". Background Byron wrote this "metaphysical drama", as he called it, after his marriage to Annabella Millbanke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASTM
ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. Some 12,575 ASTM voluntary consensus standards operate globally. The organization's headquarters is in West Conshohocken, Pennsylvania, about northwest of Philadelphia. It is founded in 1902 as the American Section of the International Association for Testing Materials (see also International Organization for Standardization). History A group of scientists and engineers, led by Charles Dudley, formed ASTM in 1898 to address the frequent rail breaks affecting the fast-growing railroad industry. The group developed a standard for the steel used to fabricate rails. Originally called the "American Society for Testing Materials" in 1902, it became the "American Society for Testing And Materials" in 1961. In 2001, ASTM official ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourier Transform
A Fourier transform (FT) is a mathematical transform that decomposes functions into frequency components, which are represented by the output of the transform as a function of frequency. Most commonly functions of time or space are transformed, which will output a function depending on temporal frequency or spatial frequency respectively. That process is also called ''analysis''. An example application would be decomposing the waveform of a musical chord into terms of the intensity of its constituent pitches. The term ''Fourier transform'' refers to both the frequency domain representation and the mathematical operation that associates the frequency domain representation to a function of space or time. The Fourier transform of a function is a complex-valued function representing the complex sinusoids that comprise the original function. For each frequency, the magnitude (absolute value) of the complex value represents the amplitude of a constituent complex sinusoid with that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Noise
In signal processing, white noise is a random signal having equal intensity at different frequencies, giving it a constant power spectral density. The term is used, with this or similar meanings, in many scientific and technical disciplines, including physics, acoustical engineering, telecommunications, and statistical forecasting. White noise refers to a statistical model for signals and signal sources, rather than to any specific signal. White noise draws its name from white light, although light that appears white generally does not have a flat power spectral density over the visible band. In discrete time, white noise is a discrete signal whose samples are regarded as a sequence of serially uncorrelated random variables with zero mean and finite variance; a single realization of white noise is a random shock. Depending on the context, one may also require that the samples be independent and have identical probability distribution (in other words independent and iden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pink Noise
Pink noise or noise is a signal or process with a frequency spectrum such that the power spectral density (power per frequency interval) is inversely proportional to the frequency of the signal. In pink noise, each octave interval (halving or doubling in frequency) carries an equal amount of noise energy. Pink noise sounds like a waterfall. It is often used to tune loudspeaker systems in professional audio. Pink noise is one of the most commonly observed signals in biological systems. The name arises from the pink appearance of visible light with this power spectrum. This is in contrast with white noise which has equal intensity per frequency interval. Definition Within the scientific literature, the term 1/f noise is sometimes used loosely to refer to any noise with a power spectral density of the form S(f) \propto \frac, where ''f'' is frequency, and 0 < α < 2, with exponent α usually close to 1. One-dimensional signals with α = 1 are usually called pink noise. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colors Of Noise
In audio engineering, electronics, physics, and many other fields, the color of noise or noise spectrum refers to the power spectrum of a noise signal (a signal produced by a stochastic process). Different colors of noise have significantly different properties. For example, as audio signals they will sound different to human ears, and as images they will have a visibly different texture. Therefore, each application typically requires noise of a specific color. This sense of 'color' for noise signals is similar to the concept of timbre in music (which is also called "tone color"; however, the latter is almost always used for sound, and may consider very detailed features of the spectrum). The practice of naming kinds of noise after colors started with white noise, a signal whose spectrum has equal power within any equal interval of frequencies. That name was given by analogy with white light, which was (incorrectly) assumed to have such a flat power spectrum over the visib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blank (cartridge)
A blank is a firearm cartridge that, when fired, does not shoot a projectile like a bullet or pellet, but generates a muzzle flash and an explosive sound ( muzzle report) like a normal gunshot would. Firearms may need to be modified to allow a blank to cycle the action, and the shooter experiences less recoil with a blank than with a live round. Blanks are often used in prop guns for shooting simulations that have no need for ballistic results, but still demand light and sound effects, such as in historical reenactments, special effects for theatre, movie and television productions, combat training, for signaling (see starting pistol), and cowboy mounted shooting. Specialised blank cartridges are also used for their propellant force in fields as varied as construction, shooting sports, and fishing and general recreation. While blanks are less dangerous than live ammunition, they are dangerous and can still cause fatal injuries. Beside the explosive gases, any objects in the cartri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impulse Noise (audio)
Impulse noise is a category of ( acoustic) noise that includes unwanted, almost instantaneous (thus impulse-like) sharp sounds (like clicks and pops)—typically caused by electromagnetic interference, scratches on disks, gunfire, explosions, and synchronization issues in digital audio. High levels of such a noise (200+ decibels) may damage internal organs, while 180 decibels are enough to damage human ears. An impulse noise filter can enhance the quality of noisy signals to achieve robustness in pattern recognition and adaptive control systems. A classic filter used to remove impulse noise is the median filter, at the expense of signal degradation. Thus it's quite common to get better performing impulse noise filters with model-based systems, which are programmed with the time and frequency properties of the noise to remove only impulse obliterated samples. See also * Audio synchronizer * Crackling noise * Record restoration * Gaussian noise Gaussian noise, named after Car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Level Meter
A sound level meter (also called sound pressure level meter (SPL)) is used for acoustic measurements. It is commonly a hand-held instrument with a microphone. The best type of microphone for sound level meters is the condenser microphone, which combines precision with stability and reliability. The diaphragm of the microphone responds to changes in air pressure caused by sound waves. That is why the instrument is sometimes referred to as a sound pressure level meter (SPL). This movement of the diaphragm, i.e. the sound pressure (unit pascal, Pa), is converted into an electrical signal (unit volt, V). While describing sound in terms of sound pressure, a logarithmic conversion is usually applied and the sound pressure ''level'' is stated instead, in decibels (dB), with 0 dB SPL equal to 20 micropascals. A microphone is distinguishable by the voltage value produced when a known, constant root mean square sound pressure is applied. This is known as microphone sensitivity. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
