source file: mills2.txt Date: Fri, 20 Sep 1996 03:21:55 -0700 Subject: Farey From: Manuel.Op.de.Coul@ezh.nl (Manuel Op de Coul) Well, the Scala command Paul E. referred to is "ratio/farey", the command "farey" does something different. It takes two parameters, an interval and the maximum Farey order (maximum denominator) of the approximating ratio. For example, rat/fa 115.0 20 gives: 9/8 203.9100 cents, 2^-3.3^2 Deviation: 88.9100 cents, Certainties: 0.0000 0.0000 10/9 182.4037 cents, 2.3^-2.5 Deviation: 67.4037 cents, Certainties: 0.0000 0.0006 11/10 165.0042 cents, 2^-1.5^-1.11 Deviation: 50.0042 cents, Certainties: 0.0000 0.0055 12/11 150.6371 cents, 2^2.3.11^-1 Deviation: 35.6371 cents, Certainties: 0.0003 0.0209 13/12 138.5727 cents, 2^-2.3^-1.13 Deviation: 23.5727 cents, Certainties: 0.0063 0.0438 14/13 128.2982 cents, 2.7.13^-1 Deviation: 13.2982 cents, Certainties: 0.0339 0.0627 15/14 119.4428 cents, 2^-1.3.5.7^-1 Deviation: 4.4428 cents, Certainties: 0.0652 0.0698 16/15 111.7313 cents, 2^4.3^-1.5^-1 Deviation: -3.2687 cents, Certainties: 0.0634 0.0658 The certainties indicate the likelihood of the interval being heard as such. The first assumes a precision of pitch perception of 0.006 (fine, 0.6%), the second of 0.012 (coarse) within a certain optimal frequency range. This is explained in an article by Goldstein. The likelihood decreases with the difference and with the denominator of the approximation. Manuel Op de Coul coul@ezh.nl Received: from ns.ezh.nl [137.174.112.59] by vbv40.ezh.nl with SMTP-OpenVMS via TCP/IP; Fri, 20 Sep 1996 12:21 +0200 Received: by ns.ezh.nl; (5.65v3.2/1.3/10May95) id AA06580; Fri, 20 Sep 1996 12:22:43 +0200 Received: from eartha.mills.edu by ns (smtpxd); id XA07900 Received: from by eartha.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI) for id DAA25081; Fri, 20 Sep 1996 03:22:40 -0700 Date: Fri, 20 Sep 1996 03:22:40 -0700 Message-Id: <009A8A764D6FFD40.F61C@vbv40.ezh.nl> Errors-To: madole@ella.mills.edu Reply-To: tuning@eartha.mills.edu Originator: tuning@eartha.mills.edu Sender: tuning@eartha.mills.edu