From analogue-request@magnus.acs.ohio-state.edu Thu Apr 8 12:19:20 1993 Received: by quark.magnus.acs.ohio-state.edu (5.65/3.910213) id AA25404; Thu, 8 Apr 93 12:19:09 -0400 Errors-To: analogue-request@magnus.acs.ohio-state.edu Sender: analogue-request@magnus.acs.ohio-state.edu Received: from teradyne.com by quark.magnus.acs.ohio-state.edu (5.65/3.910213) id AA25399; Thu, 8 Apr 93 12:19:07 -0400 Received: from ICD.Teradyne.COM ([131.101.176.2]) by red1.Teradyne.COM (4.1/SMI-4.1/TERX-1.2) id AA25244; Thu, 8 Apr 93 09:18:53 PDT Received: by ICD.Teradyne.COM (4.1/SMI-4.1/TER-1.26/attain-1.23+2) id AA10254; Thu, 8 Apr 93 09:18:31 PDT Received: from midas.teradyne.com (midas.std.teradyne.com) by teradyne.com (4.1/SMI-4.1/TER-1.17/teradyne-1.3a/jxh) id AA11699; Thu, 8 Apr 93 09:18:57 PDT Received: from volt.teradyne.com by midas.teradyne.com (4.1/SMI-4.1) id AA03836; Thu, 8 Apr 93 09:18:58 PDT Date: Thu, 8 Apr 93 09:18:58 PDT From: rogoff@teradyne.com (David Rogoff x4627) Message-Id: <9304081618.AA03836@midas.teradyne.com> To: analogue@magnus.acs.ohio-state.edu Subject: Re: great "universal midi box" project Status: OR Here we're touching an interesting subject for us into analogue synth electronics. Just two thoughts from the back of my head... 1. The Matrix-6/6R and Cheetah MS-6 use two sample and hold circuits for each analog CV. One of them has a much longer time constant, so the CPU can decide how fast it wants the CV to move, and avoid zipper noise. 2. In my own synth I use integrators to actually generate ramps between CV increments in the EG's and LFO's. Result: no zipper (but more complicated s&h's). /Ricard This is great for real VCOs. Eventually I want to use digital oscillators, so there is no sample/hold or integrator. That's why I need to know how fast I can jump the frequency - to make the integrator in software, if you will. David From analogue-request@magnus.acs.ohio-state.edu Thu Apr 8 04:35:38 1993 Received: by quark.magnus.acs.ohio-state.edu (5.65/3.910213) id AA09435; Thu, 8 Apr 93 04:35:27 -0400 Errors-To: analogue-request@magnus.acs.ohio-state.edu Sender: analogue-request@magnus.acs.ohio-state.edu Received: from nic.lth.se by quark.magnus.acs.ohio-state.edu (5.65/3.910213) id AA09430; Thu, 8 Apr 93 04:35:26 -0400 Received: from axisab.axis.se by mail.lth.se with bsmtp (Smail3.1.28.1 #2) id m0ngr9E-000MTuC; Thu, 8 Apr 93 09:35 MET DST Received: by axisab.axis.se (/\==/\ Smail3.1.25.1 #25.6) id ; Thu, 8 Apr 93 09:35 MET DST Message-Id: From: ricard@axis.se (Ricard Wolf) Date: Thu, 8 Apr 93 09:35:04 MET DST X-Mailer: Mail User's Shell (7.0.1 12/13/89) To: rogoff@teradyne.com (David Rogoff x4627) Subject: Re: great "universal midi box" project Cc: analogue@magnus.acs.ohio-state.edu Status: OR > > Forrest Cook writes: > >P.S. The great "universal midi box" project is coming along, I've figured out > Forrest, > > you are in a great position to test something that has bothered me > (and hopefully other analog types interested in new analogish- > digital stuff): what DAC step size and/or sample rate is required > to avoid the "zipper" effect on glide/portamento. > > On any synth I've listened to (D70, JD-800, Vintage Keys etc..) if > you set portamento to a fast value (~1/4 sec for five octaves) and > then rapidly alternate between high and low keys, you will hear > this zipped or stair-case effect. > > Could you write alter your code to add portamento in the HC11 and play > with timing loops to hear the effect of different update rates? > It would be great to have this info to figure out what kind of > horsepower a digital synth would have to have to control 32 or more > voices. Here we're touching an interesting subject for us into analogue synth electronics. Just two thoughts from the back of my head... 1. The Matrix-6/6R and Cheetah MS-6 use two sample and hold circuits for each analog CV. One of them has a much longer time constant, so the CPU can decide how fast it wants the CV to move, and avoid zipper noise. 2. In my own synth I use integrators to actually generate ramps between CV increments in the EG's and LFO's. Result: no zipper (but more complicated s&h's). /Ricard -- Ricard Wolf / | \ / | /- email: ricard@axis.se Axis Communications AB /__| \/ | \__ uucp: axisab.se!ricard S - 223 70 LUND / | /\ | \ Tel: +46 46 19 18 63 SWEDEN / | / \ | \__/ Fax: +46 46 13 61 30 -- "Sweet dreams are made of this" -- From analogue-request@magnus.acs.ohio-state.edu Wed Apr 7 19:40:00 1993 Received: by quark.magnus.acs.ohio-state.edu (5.65/3.910213) id AA26316; Wed, 7 Apr 93 19:39:49 -0400 Errors-To: analogue-request@magnus.acs.ohio-state.edu Sender: analogue-request@magnus.acs.ohio-state.edu Received: from teradyne.com by quark.magnus.acs.ohio-state.edu (5.65/3.910213) id AA26308; Wed, 7 Apr 93 19:39:44 -0400 Received: from ICD.Teradyne.COM ([131.101.176.2]) by red1.Teradyne.COM (4.1/SMI-4.1/TERX-1.2) id AA23294; Wed, 7 Apr 93 16:39:29 PDT Received: by ICD.Teradyne.COM (4.1/SMI-4.1/TER-1.26/attain-1.23+2) id AA16498; Wed, 7 Apr 93 16:39:05 PDT Received: from midas.teradyne.com (midas.std.teradyne.com) by teradyne.com (4.1/SMI-4.1/TER-1.17/teradyne-1.3a/jxh) id AA10540; Wed, 7 Apr 93 16:39:26 PDT Received: from volt.teradyne.com by midas.teradyne.com (4.1/SMI-4.1) id AA01790; Wed, 7 Apr 93 16:39:24 PDT Date: Wed, 7 Apr 93 16:39:24 PDT From: rogoff@teradyne.com (David Rogoff x4627) Message-Id: <9304072339.AA01790@midas.teradyne.com> To: analogue@magnus.acs.ohio-state.edu Subject: great "universal midi box" project Status: OR Forrest Cook writes: >P.S. The great "universal midi box" project is coming along, I've figured out >how to get the 68HC11 to interpret MIDI data and deal with running status. >My old ARP Odyssey really plays well when connected to a decent keyboard. Forrest, you are in a great position to test something that has bothered me (and hopefully other analog types interested in new analogish- digital stuff): what DAC step size and/or sample rate is required to avoid the "zipper" effect on glide/portamento. On any synth I've listened to (D70, JD-800, Vintage Keys etc..) if you set portamento to a fast value (~1/4 sec for five octaves) and then rapidly alternate between high and low keys, you will hear this zipped or stair-case effect. Could you write alter your code to add portamento in the HC11 and play with timing loops to hear the effect of different update rates? It would be great to have this info to figure out what kind of horsepower a digital synth would have to have to control 32 or more voices. Thanks, David David Rogoff, Teradyne Semiconductor Test Division teradyne!rogoff@ism.isc.com rogoff@teradyne.com 818-991-2900 x4627 From dacc@cmp-rt.music.uiuc.edu Wed Apr 7 23:48:52 1993 Received: from cmp-rt.music.uiuc.edu by bottom.magnus.acs.ohio-state.edu (5.65/3.910213) id AA28041; Wed, 7 Apr 93 23:48:47 -0400 Received: by cmp-rt.music.uiuc.edu (AIX 2.1 2/4.03) id AA17212; Wed, 7 Apr 93 22:47:05 CDT Date: Wed, 7 Apr 93 22:47:05 CDT From: dacc@cmp-rt.music.uiuc.edu (Andrew C. Crowell) Message-Id: <9304080347.AA17212@cmp-rt.music.uiuc.edu> To: analogue-request@magnus.acs.ohio-state.edu Subject: Modular MIDI? Status: OR Hey, gang...I need some advice on MIDI applications with modular analog gear. More specifically, I'm looking for interfaces that'll allow MIDI->CV control of modules that use the standard 1v/8va convention for CV scaling, even better if I can find controllers that'll allow control of non-standard CV scaling implementations. Ideas/devices, anyone? D.A.C. Crowell Computer Music Project/School of Music University of Illinois at Urbana/Champaign (dacc@cmp-rt.music.uiuc.edu)