This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment some additional thoughts.... Twelve fifths - pythagorean comma =3D seven octaves =20 mathematically (3/(2^(pc/12)))^12 =3D (2)^7=20 is traditional equal temperament Twelve fifths=3D seven octaves + pythagorean comma=20 mathematically (3/2)^12 =3D (2)^(pc/7)^7 is equal pure 5th (Cordier) Twelve 12ths =3D 19 Octaves + pythagorean comma mathematically 3^12 =3D 2^(pc/19)^19 or 3^12 =3D 3^(12/19)^19 is equal pure 12th (Stopper)=20 or "acoustic octave transformed pythagorean" the list of the "pythagorean" given below is not complete, it can be = extended to any interval combination of 3 and 2 ratio of the keyboard regards, Bernhard Stopper ----- Original Message -----=20 From: Bernhard Stopper=20 To: Pianotech=20 Sent: Wednesday, June 02, 2004 9:50 PM Subject: Re: P12 in Tunelab Pro / P12 theoretical basics OOPs, send click was done to fast, the first version has to be = corrected by some * in the math and the final statement.... ----- Original Message -----=20 From: Bernhard Stopper=20 To: Pianotech=20 Sent: Wednesday, June 02, 2004 9:37 PM Subject: P12 in Tunelab Pro / P12 theoretical basics Ric, I agree that the tuning itself was tendencially practiced more or = less by good tuners already long time ago.=20 What i claim as new is mainly the theory behind the P12 tuning. = Especially the transformation of the standard 12-5th circle that has to = be closed with 7 octaves into a 12-12th circle that is closed with 19 = octaves. And the direct transformation of the pythagorean tuning into = equal P12 by replacing simply the mathmatical 2/1 octave ratio with the = "acoustic octave" (later explained).=20 (The effect of inharmonicity can be divided out at this point, it is = added later as instrument immanent factor that stretches all ratios = according to the instrument inharmonicity curve) For those who are not familiar with any maths the traditional fifth = circle can be expressed in words as Twelve fifths =3D seven octaves + pythagorean comma Mathematically this can be written as ( 3/2 for 5th, pc for = pythagorean comma and 2 for octave ratio): (3/2)^12 =3D (2)^7 * pc Now comes the transformation trick: Dividing out the twelve fifths give: (3^12) / (2^12) =3D 2^7 * pc Sorting 3 (Pure 12th) and 2 (Pure octave) give: 3^12 =3D 2^12 * 2^7 * pc=20 =3D> 3^12 =3D 2^19 * pc This describes a 12-P12 circle that is closed by 19 Octaves + = pythagorean comma=20 (what itself is the base for a new musical system i called = "Dodecachord" not mentioned here in detail). In P12 tuning, the pythagorean comma is divided in 19 parts and = added evenly to the octaves that become 1,2 cent wider than pure (in the = instrument, inharmonicity must be added here). The factor for one keystep is the 19th root of 3. Every of 1/19 pythagorean comma stretched octave can be now = rewritten as 2^(pc/19) or 3^(12/19) instead of the 2. I call this = "acoustic octave" since pure octaves with a ratio of 2 don=B4t sound = "just" when played melodically. (what has been proven in many = investigations) Now let=B4s look at the pythagorean intervals: 2/1 (Octave) 3/1 (P12) 3/2 (5th) 4/3 (4th) 9/8 (M sec.) 81/64 (M3rd) 256/243 (m sec.) All can be split down into ratios of octaves 12ths and rewritten as=20 2^1/1 3^1/1 3^1/2^1 2^2/3^1 3^2/2^3 3^4/2^6 2^8/3^5 Substituting the mathematical octave ratio 2 with the P12=B4s = "acoustic octave" 2^(pc/19) or 3^(12/19) Now results in 2^1/1 3^1/1 3^1/3^(12/19)^1 3^(12/19)^2/3^1 3^2/3^(12/19)^3 3^4/3^(12/19)^6 3^(12/19)^8/3^5 So in consequence can be said: Equal temperament based on Pure 12ths* is the direct transformation = of the pythagorean tuning by simply replacing the mathematical octave = ratio of 2 with the acoustic ocatve ratio of 3^(12/19). I find this philosphically somehow interesting/important. *published as "Stopper Tuning" in euro-piano 3/1988 ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/aa/21/b4/76/attachment.htm ---------------------- multipart/alternative attachment--
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