Английская Википедия:Beta scale

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Шаблон:Short description

Файл:Perfect fourth on C.png
Perfect fourth (just: 498.04 cents Шаблон:Audio, 12-tet: 500 cents Шаблон:Audio, Beta scale: 512 cents Шаблон:Audio)

Шаблон:Multiple image

The β (beta) scale is a non-octave-repeating musical scale invented by Wendy Carlos and first used on her album Beauty in the Beast (1986). It is derived from approximating just intervals using multiples of a single interval without, as is standard in equal temperaments, requiring an octave (2:1). It may be approximated by splitting the perfect fifth (3:2) into eleven equal parts [(3:2)Шаблон:Sup ≈ 63.8 cents]. It may be approximated by splitting the perfect fourth (4:3) into two equal parts [(4:3)Шаблон:Sup],[1] or eight equal parts [(4:3)Шаблон:Sup = 64 cents],[2] totaling approximately 18.8 steps per octave.

The scale step may also precisely be derived from using 11:6 (BШаблон:MusicШаблон:MusicШаблон:Music, 1049.36 cents, Шаблон:Audio) to approximate the interval Шаблон:Frac,[3] which equals 6:5 Шаблон:Audio. Шаблон:Blockquote

<math>\frac{11\log_2{(3/2)}+6\log_2{(5/4)}+5\log_2{(6/5)}}{11^2+6^2+5^2}=0.05319411048</math> and <math>0.05319411048\times1200=63.832932576</math> (Шаблон:Audio)

Although neither has an octave, one advantage to the beta scale over the alpha scale is that 15 steps, 957.494 cents, Шаблон:Audio is a reasonable approximation to the seventh harmonic (7:4, 968.826 cents)[3][4] Шаблон:Audio though both have nice triads[1] (Шаблон:Audio, Шаблон:Audio, and Шаблон:Audio). "According to Carlos, beta has almost the same properties as the alpha scale, except that the sevenths are slightly more in tune."[1]

The delta scale may be regarded as the beta scale's reciprocal since it is "as far 'down' the (0 3 6 9) circle from α as β is 'up'."[5]

interval name size
(steps)
size
(cents)
just ratio just
(cents)
error
major second 3 191.50 9:8 203.91 −12.41
minor third 5 319.16 6:5 315.64 +3.52
major third 6 383.00 5:4 386.31 −3.32
perfect fifth 11 702.16 3:2 701.96 +0.21
harmonic seventh 15 957.49 7:4 968.83 −11.33
octave 18 1148.99 2:1 1200.00 −51.01
octave 19 1212.83 2:1 1200.00 +12.83

See also

References

Шаблон:Reflist

External links

Шаблон:Microtonal music Шаблон:Musical tuning Шаблон:Scales Шаблон:Wendy Carlos

  1. 1,0 1,1 1,2 Milano, Dominic (November 1986). "A Many-Colored Jungle of Exotic Tunings", Keyboard.
  2. Carlos, Wendy (2000/1986). "Liner notes", Beauty in the Beast. ESD 81552.
  3. 3,0 3,1 Benson, Dave (2006). Music: A Mathematical Offering, p.232-233. Шаблон:ISBN. "Carlos has 18.809 β-scale degrees to the octave, corresponding to a scale degree of 63.8 cents."
  4. Sethares, William (2004). Tuning, Timbre, Spectrum, Scale, p.60. Шаблон:ISBN. Scale step of 63.8 cents.
  5. Taruskin, Richard (1996). Stravinsky and the Russian Traditions: A Biography of the Works through Mavra, p.1394. Шаблон:ISBN.