Beta scale

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Perfect fourth (just: 498.04 cents About this soundPlay (help·info), 12-tet: 500 cents About this soundPlay (help·info), Beta scale: 512 cents About this soundPlay (help·info))
Chromatic circle
Comparing the beta scale's approximations with the just values
Twelve-tone equal temperament vs. just

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)1⁄11 ≈ 63.8 cents]. It may be approximated by splitting the perfect fourth (4:3) into two equal parts [(4:3)1⁄2],[1] or eight equal parts [(4:3)1⁄8 = 64 cents],[2] totaling approximately 18.8 steps per octave.

The scale step may also precisely be derived from using 11:6 (B↑♭-, 1049.36 cents, About this soundPlay (help·info)) to approximate the interval 3:2⁄5:4,[3] which equals 6:5 About this soundPlay (help·info).

In order to make the approximation as good as possible we minimize the mean square deviation. ... We choose a value of the scale degree so that eleven of them approximate a 3:2 perfect fifth, six of them approximate a 5:4 major third, and five of them approximate a 6:5 minor third.[3]

and (About this soundPlay (help·info))

Although neither has an octave, one advantage to the beta scale over the alpha scale is that 15 steps, 957.494 cents, About this soundPlay (help·info) is a reasonable approximation to the seventh harmonic (7:4, 968.826 cents)[3][4] About this soundPlay (help·info) though both have nice triads[1] (About this soundPlay major triad (help·info), About this soundminor triad (help·info), and About this sounddominant seventh (help·info)). "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
minor third 5 319.00 6:5 315.64 +3.35
major third 6 382.80 5:4 386.31 −3.52
perfect fifth 11 701.79 3:2 701.96 −0.16
harmonic seventh 15 956.99 7:4 968.83 −11.84

See also[]

Sources[]

  1. ^ Jump up to: a b c 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. ^ Jump up to: a b c Benson, Dave (2006). Music: A Mathematical Offering, p.232-233. ISBN 0-521-85387-7. "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. ISBN 1-85233-797-4. Scale step of 63.8 cents.
  5. ^ Taruskin, Richard (1996). Stravinsky and the Russian Traditions: A Biography of the Works through Mavra, p.1394. ISBN 0-520-07099-2.

External links[]

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