翻訳と辞書 Words near each other ・ Melachittakadu ・ Melachokkanathapuram ・ Melacoryphus lateralis ・ Meladeia ・ Meladema ・ Meladema coriacea ・ Meladema imbricata ・ Meladema lanio ・ Melado River ・ Meladrazine ・ Melady ・ Melady House ・ Melaeninae ・ Mel Sage ・ Mel Sampat ・ Mel scale ・ Mel Schacher ・ Mel Schrieberg ・ Mel Schwartz ・ Mel Scott ・ Mel Sembler ・ Mel Semenko ・ Mel Shapiro ・ Mel Sharples ・ Mel Shaw ・ Mel Sheppard ・ Mel Showers ・ Mel Silver ・ Mel Simons ・ Mel Sithamur Jain Math Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Mel scale ： ウィキペディア英語版 Mel scale The mel scale, named by Stevens, Volkmann, and Newman in 1937,〔 〕 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. As a result, four octaves on the hertz scale above 500 Hz are judged to comprise about two octaves on the mel scale. The name mel comes from the word melody to indicate that the scale is based on pitch comparisons. A popular formula to convert $f$ hertz into $m$ mel is:〔 〕 :$m\; =\; 2595\; \backslash log\_\backslash left(1\; +\; \backslash frac\backslash right)$ ==History and other formulas== There is no single mel-scale formula.〔 〕 The popular formula from O'Shaugnessy's book can be expressed with different log bases: :$m\; =\; 2595\; \backslash log\_\backslash left(1\; +\; \backslash frac\backslash right)\; =\; 1127\; \backslash log\_e\backslash left(1\; +\; \backslash frac\backslash right)\; \backslash$ The corresponding inverse expressions are: :$f\; =\; 700(10^\; -\; 1)\; =\; 700(e^\; -\; 1)\; \backslash$ There were published curves and tables on psychophysical pitch scales since Steinberg's 1937〔 〕 curves based on just-noticeable differences of pitch. More curves soon followed in Fletcher and Munson's 1937〔 〕 and Fletcher's 1938〔 〕 and Stevens' 1937〔 and Stevens and Volkmann's 1940〔 〕 papers using a variety of experimental methods and analysis approaches. In 1949 Koenig published an approximation based on separate linear and logarithmic segments, with a break at 1000 Hz.〔 〕 Gunnar Fant proposed the current popular linear/log formula in 1949, but with the 1000 Hz corner frequency.〔 Gunnar Fant (1949) "Analys av de svenska konsonantljuden : talets allmänna svängningsstruktur", LM Ericsson protokoll H/P 1064 〕 An alternate expression of the formula, not depending on choice of log base, is noted in Fant (1968):〔Fant, Gunnar. (1968). Analysis and synthesis of speech processes. In B. Malmberg (Ed.), ''Manual of phonetics'' (pp. 173-177). Amsterdam: North-Holland.〕〔 〕 :$m\; =\; \backslash frac\; \backslash log\backslash left(1\; +\; \backslash frac\backslash right)\; \backslash$ In 1976, Makhoul and Cosell published the now-popular version with the 700 Hz corner frequency.〔 〕 As Ganchev et al. have observed, "The formulae (700 ), when compared to (with 1000 ), provide a closer approximation of the Mel scale for frequencies below 1000 Hz, at the price of higher inaccuracy for frequencies higher than 1000 Hz."〔 〕 Above 7 kHz, however, the situation is reversed, and the 700 Hz version again fits better. Data by which some of these formulas are motivated are tabulated in Beranek (1949), as measured from the curves of Stevens and Volkmann:〔Beranek, Leo L. (1949). ''Acoustic measurements''. New York: McGraw-Hill.〕 A formula with a break frequency of 625 Hz is given by Lindsay & Norman (1977);〔Lindsay, Peter H.; & Norman, Donald A. (1977). ''Human information processing: An introduction to psychology'' (2nd ed.). New York: Academic Press.〕 the formula doesn't appear in their 1972 first edition: :$m\; =\; 2410\; \backslash log\_(1.6\backslash times10^\; f\; +\; 1)$ Most mel-scale formulas give exactly 1000 mels at 1000 Hz. The break frequency (e.g. 700 Hz, 1000 Hz, or 625 Hz) is the only free parameter in the usual form of the formula. Some non-mel auditory-frequency-scale formulas use the same form but with much lower break frequency, not necessarily mapping to 1000 at 1000 Hz; for example the ERB-rate scale of Glasberg & Moore (1990) uses a break point of 228.8 Hz,〔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.〕 and the cochlear frequency–place map of Greenwood (1990) uses 165.3 Hz.〔Greenwood, D. D. (1990). A cochlear frequency–position function for several species—29 years later. ''The Journal of the Acoustical Society of America'', 87, 2592–2605.〕 Other functional forms for the mel scale have been explored by Umesh et al.; they point out that the traditional formulas with a logarithmic region and a linear region do not fit the data from Stevens and Volkmann's curves as well as some other forms, based on the following data table of measurements that they made from those curves:〔 〕 Donald D Greenwood, a student of Stevens who worked on the mel scale experiments in 1956, considers the scale biased by experimental flaws, and posted in 2009 to a mailing list:〔http://lists.mcgill.ca/scripts/wa.exe?A2=ind0907d&L=auditory&P=389〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mel scale」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.