source file: mills2.txt Subject: Pitch Bend Tuning From: asouter@scf.usc.edu (Andrew Souter) Friends, I am attempting to use pitch bend messages sent by sequencer to a K2000 to set frequency output to conform to JI ratios in a more perfect fashion than possible using Global software tuning or other cent based methods. I sent the following message to the list last week: > This is a rather basic question I know, but does anyone know what >the tuning resolution of the K2000? How many steps are possible between a >semitone, and if this number is something like 2048 or hopefully 4096, how >are translations made between this number and cent values? Thanks in >advance. _______________________________________________________________________________ I recieved the following response from John at Kurweil: If you're speaking in terms of the intonation tables, resolution is limited to 1 cent steps by software. The value set in software is truncated, not rounded, to the next lowest hardware resolution, which is on the order of 1/20 cent. Transposing samples downwards 4-5 octaves or more reduces the tuning resolution. Changing pitch by other means such was the pitch wheel will usually be more limited by the controller than the K2000 internals. Most if not all of the pitch wheels of current synthesizers have a resolution of only 7-8 bits, even though the MIDI parameter has a resolution to 14 bits. _______________________________________________________________________________ I still have several unanswered questions concerning generally using the pitch benf message to control tuning, and more specifically doing this on a K2000. Let me further clarify my query with the following questions: 1) Where does the 1/20 of a cent figure come from? Does that mean that there are 2000 (or probably 2048) possible frequency divisions between a musical half step? 2) In the hypothetical scenario where the pitch bend range is set to 100 cents under the "Common" page, and MIDI pitch bend messages are sent using an external sequencer to produce every possible value in step size of 1 unit (0,1,2,3... ...8189,8190,8191) from 0 to 8191, how many unique pitch values will the K2000 produce? Is it capable of producing 8192 unique values? Is the figure dependent upon the initial frequency of the note? 3) Would I be correct in assuming that pitch bend messages affect the absolute output frequency in an exponential fashion as in the 12Tet model? What I mean is, if I played A440 and with a pitch bend value of 256 (and pitch bend range was set to 100 cents) would the output frequency in Hertz be equal to 440((2^(1/12))^(256/8192))=440.7949Hz? thanks... -andrew Safe Journey... Received: from ns.ezh.nl [137.174.112.59] by vbv40.ezh.nl with SMTP-OpenVMS via TCP/IP; Fri, 15 Nov 1996 11:02 +0100 Received: by ns.ezh.nl; (5.65v3.2/1.3/10May95) id AA11462; Fri, 15 Nov 1996 11:04:08 +0100 Received: from eartha.mills.edu by ns (smtpxd); id XA11479 Received: from by eartha.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI) for id CAA18012; Fri, 15 Nov 1996 02:03:44 -0800 Date: Fri, 15 Nov 1996 02:03:44 -0800 Message-Id: <961115100106_71670.2576_HHB42-3@CompuServe.COM> Errors-To: madole@ella.mills.edu Reply-To: tuning@eartha.mills.edu Originator: tuning@eartha.mills.edu Sender: tuning@eartha.mills.edu