Not exactly, since you should take 440 * 3,somewhat^(1/19) (because of inharmonicity of the 3rd harmonic what is not negligible at this point). But i think we can say that the aural integration of the octave spectrum fits much better to inharmonicity in P12 than with standard-ET octaves. (The "acoustic octave" effect.) friendly wishes. Bernhard ----- Original Message ----- From: "Richard Brekne" <Richard.Brekne@grieg.uib.no> To: "Pianotech" <pianotech@ptg.org> Sent: Thursday, June 03, 2004 12:44 AM Subject: Re: P12 in Tunelab Pro / P12 theoretical basics > Hi Bernhard > > Hi again Bernhard > > So lets put this into some more perspective... this is getting really > interesting by the way... my attention is really caught ! > > The pythagorean comma of roughly 23.46 is usually divided into 12 parts > gives 1.955 cents needed to yeild a pure 2:1 octave. If we divide the > comma into 19 parts then we have as you say roughly 1.235 cents needed > to end up with a pure 3:1 12th > > Translated into our familiar root of twelve and root of nineteen and > useing 440 as an example... : > > 440 * 2^(1/12) twelve times will yeild 880, but 440 * 3^(1/19) twelve > times will yeild 880.6278 for the 2:1 relationship. Adding abou 0.63 bps > before inharmonicity is considered to the A3-A4 octave. Now.... if you > tune an A3-A4 octave to a pure 6:3 octave type... then the 2:1 type gets > stretched by a very comparable amount.... i.e. close to 0.63 bps for the 2:1 > > One of my thoughts all along about the P12th that I do is that it more > or less automatically takes consideration to inharmoncity. > > Just a thought > > RicB > > > > > > > Bernhard Stopper wrote: > > > some additional thoughts.... > > > > *Twelve fifths - pythagorean comma = seven octaves* > > mathematically *(3/(2^(pc/12)))^12 = (2)^7* > > is *traditional equal temperament* > > > > *Twelve fifths= seven octaves + pythagorean comma* > > mathematically *(3/2)^12 = (2)^(pc/7)^7* > > is *equal pure 5th (Cordier)* > > > > *Twelve 12ths = 19 Octaves + pythagorean comma* > > mathematically *3^12 = 2^(pc/19)^19* > > *or* > > *3^12 = 3^(12/19)^19* > > *is equal pure 12th *(Stopper)* * > > *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 > > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives
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