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Mel Scale
The mel scale (after the word ''melody'') is a perceptual scale of pitches judged by listeners to be equal in distance from one another. The reference point between this scale and normal frequency measurement is defined by assigning a perceptual pitch of 1000 mels to a 1000 Hz tone, 40 dB above the listener's threshold. Above about 500 Hz, increasingly large intervals are judged by listeners to produce equal pitch increments. Formula A formula to convert ''f'' hertz into ''m'' mels is: m = 2595 \log_\left(1 + \frac\right) History and other formulas The formula from O'Shaughnessy's book can be expressed with different logarithmic bases: m = 2595 \log_\left(1 + \frac\right) = 1127 \ln\left(1 + \frac\right) The corresponding inverse expressions are: f = 700\left(10^\frac - 1\right) = 700\left(e^\frac - 1\right) There were published curves and tables on psychophysical pitch scales since Steinberg's 1937 curves based on just-noticeable differences of pitch. Mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A440
A440 or A-440 may refer to: * A440 (pitch standard) * A440 highway (Australia), a road in Victoria, Australia * Quebec Autoroute 440 (Laval) * Quebec Autoroute 440 (Quebec City) See also * Apollo 440 Apollo 440 (also known as Apollo Four Forty or @440) are a British electronic music group formed in Liverpool in 1990. The group has written, recorded, and produced five studio albums, collaborated with and produced other artists, remixed as ..., an English band * Airbus A400M, a military transport aircraft * Archimedes 440, abbreviated to A440 - one of the Acorn Archimedes range of RISC computers {{Letter-NumberCombDisambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melody
A melody (from Greek language, Greek μελῳδία, ''melōidía'', "singing, chanting"), also tune, voice or line, is a Linearity#Music, linear succession of musical tones that the listener perceives as a single entity. In its most literal sense, a melody is a combination of pitch (music), pitch and rhythm, while more figuratively, the term can include other musical elements such as Timbre, tonal color. It is the foreground to the background accompaniment. A line or part (music), part need not be a foreground melody. Melodies often consist of one or more musical Phrase (music), phrases or Motif (music), motifs, and are usually repeated throughout a musical composition, composition in various forms. Melodies may also be described by their melodic motion or the pitches or the interval (music), intervals between pitches (predominantly steps and skips, conjunct or disjunct or with further restrictions), pitch range, tension (music), tension and release, continuity and coheren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitch (music)
Pitch is a perceptual property of sounds that allows their ordering on a frequency-related scale, or more commonly, pitch is the quality that makes it possible to judge sounds as "higher" and "lower" in the sense associated with musical melodies. Pitch is a major auditory attribute of musical tones, along with duration, loudness, and timbre. Pitch may be quantified as a frequency, but pitch is not a purely objective physical property; it is a subjective psychoacoustical attribute of sound. Historically, the study of pitch and pitch perception has been a central problem in psychoacoustics, and has been instrumental in forming and testing theories of sound representation, processing, and perception in the auditory system. Perception Pitch and frequency Pitch is an auditory sensation in which a listener assigns musical tones to relative positions on a musical scale based primarily on their perception of the frequency of vibration. Pitch is closely related to frequency, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decibel
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 10 (approximately ). The unit expresses a relative change or an absolute value. In the latter case, the numeric value expresses the ratio of a value to a fixed reference value; when used in this way, the unit 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"). Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the logarithm in base 10. That is, a change in ''power'' by a factor of 10 corresponds to a 10 dB change in level. When expressing root-power quantities, a change in ''ampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interval (music)
In music theory, an interval is a difference in pitch between two sounds. An interval may be described as horizontal, linear, or melodic if it refers to successively sounding tones, such as two adjacent pitches in a melody, and vertical or harmonic if it pertains to simultaneously sounding tones, such as in a chord. In Western music, intervals are most commonly differences between notes of a diatonic scale. Intervals between successive notes of a scale are also known as scale steps. The smallest of these intervals is a semitone. Intervals smaller than a semitone are called microtones. They can be formed using the notes of various kinds of non-diatonic scales. Some of the very smallest ones are called commas, and describe small discrepancies, observed in some tuning systems, between enharmonically equivalent notes such as C and D. Intervals can be arbitrarily small, and even imperceptible to the human ear. In physical terms, an interval is the ratio between two sonic freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Just-noticeable Difference
In the branch of experimental psychology focused on sense, sensation, and perception, which is called psychophysics, a just-noticeable difference or JND is the amount something must be changed in order for a difference to be noticeable, detectable at least half the time. This limen is also known as the difference limen, difference threshold, or least perceptible difference. Quantification For many sensory modalities, over a wide range of stimulus magnitudes sufficiently far from the upper and lower limits of perception, the 'JND' is a fixed proportion of the reference sensory level, and so the ratio of the JND/reference is roughly constant (that is the JND is a constant proportion/percentage of the reference level). Measured in physical units, we have: \frac = k, where I\! is the original intensity of the particular stimulation, \Delta I\! is the addition to it required for the change to be perceived (the JND), and ''k'' is a constant. This rule was first discovered by Erns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunnar Fant
Carl Gunnar Michael Fant (October 8, 1919 – June 6, 2009) was a leading researcher in speech science in general and speech synthesis in particular who spent most of his career as a professor at the Swedish Royal Institute of Technology (KTH) in Stockholm. He was a first cousin of the actors and directors George Fant and Kenne Fant. Gunnar Fant received a Master of Science in Electrical Engineering from KTH in 1945. He specialized in the acoustics of the human voice, measuring formant values, and continued to work in this area at Ericsson and at the Massachusetts Institute of Technology. He also took the initiative of creating a speech communication department at KTH, unusual at the time. Fant's work led to the birth of a new era of speech synthesis with the introduction of powerful and configurable formant synthesizers. In 1960 he published the source-filter model of speech production, which became widely used. In the 1960s, Gunnar Fant's Orator Verbis Electris (OVE) competed w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Makhoul
John Makhoul is a Lebanese-American computer scientist who works in the field of speech and language processing. Dr. Makhoul's work on linear predictive coding was used in the establishment of the Network Voice Protocol, which enabled the transmission of speech signals over the ARPANET. Makhoul is recognized in the field for his vital role in the areas of speech and language processing, including speech analysis, speech coding, speech recognition and speech understanding. He has made a number of significant contributions to the mathematical modeling of speech signals, including his work on linear prediction, and vector quantization. His patented work on the direct application of speech recognition techniques for accurate, language-independent optical character recognition (OCR) has had a dramatic impact on the ability to create OCR systems in multiple languages relatively quickly. Dr. Makhoul is a Chief Scientist at BBN Technologies, where he has led several successful research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equivalent Rectangular Bandwidth
The equivalent rectangular bandwidth or ERB is a measure used in psychoacoustics, which gives an approximation to the bandwidths of the filters in human hearing, using the unrealistic but convenient simplification of modeling the filters as rectangular band-pass filters, or band-stop filters, like in tailor-made notched music training (TMNMT). Approximations For moderate sound levels and young listeners, the bandwidth of human auditory filters can be approximated by the polynomial equation: where ''f'' is the center frequency of the filter in kHz and ERB(''f'') is the bandwidth of the filter in Hz. The approximation is based on the results of a number of published simultaneous masking experiments and is valid from 0.1 to 6.5 kHz.B.C.J. Moore and B.R. Glasberg, "Suggested formulae for calculating auditory-filter bandwidths and excitation patterns" Journal of the Acoustical Society of America 74: 750-753, 1983. The above approximation was given in 1983 by Moore and Glasber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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