source file: mills2.txt Date: Tue, 19 Mar 1996 09:55:54 -0800 Subject: calculating cents for ratios From: Phil Burk John writes: > Of course, if one is using JI, then simply memorizing the cent values ofa small set of key intervals such as 3/2, 5/4, 7/4, 11/8, 13/8, etc. would be sufficient. I don't read this list all the time so forgive me if someone has already written about this....... Since cents are logarithmic, for JI, one perform division by subtracting cents. Thus one need only keep a table of the cent values for the prime integers. To calculate the cents value for a ratio, just subtract the cents for the denominator from the numerator. 1 -- 0 2 -- 1200 3 -- 1902 4 -- 2400 5 -- 2786 So for cents for 3/2 = 1902 - 1200 = 702 The same principle applies for pitch bend because it is also logarithmic. I use this trick in a relative intonation score entry system in HMSL to rapidly calculate pitch bend values for ratios without using transcendentals. Phil Burk Received: from eartha.mills.edu [144.91.3.20] by vbv40.ezh.nl with SMTP-OpenVMS via TCP/IP; Tue, 19 Mar 1996 23:28 +0100 Received: from by eartha.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI) for id OAA18765; Tue, 19 Mar 1996 14:27:54 -0800 Date: Tue, 19 Mar 1996 14:27:54 -0800 Message-Id: <1BAE3F22D1@rice.houstonisd.k12.tx.us> Errors-To: madole@ella.mills.edu Reply-To: tuning@eartha.mills.edu Originator: tuning@eartha.mills.edu Sender: tuning@eartha.mills.edu