high-res interface between Max/MSP and analog CV

    Feb 27 2006 | 9:39 pm
    Can someone shed some light on high-resolution interfaces between Max/MSP and analog control voltages?
    Phil Rees and Kenton have a 16 bit DAC-based converter, I see...
    Is there anything beyond MIDI?

    • Feb 28 2006 | 7:43 am
      Hi Matt,
      The Miditron can handle analogue in with a range of 0-16383 using Pitch bend. See www.eroktronix.com.
    • Feb 28 2006 | 6:11 pm
      The MidiTron automatically gives 10-bit resolution when you set the message mode to pitch bend for an analog terminal. You can have up to ten 10-bit analog ins by using pitch bend on 10 different MIDI channels.
      ******************************************** * MidiTron MIDI to Real World Interface * * Now available from http://eroktronix.com * * Only $149 * ********************************************
    • Feb 28 2006 | 8:51 pm
      Isn't the original poster looking for something that works the other way around, i.e. provides high-res analog *output*?
      PWM is a cheap alternative to generate quasi-analog outputs w/o the need for a DAC. It works very well to control motors and lights. The MidiTron provides PWM (up tp 20?), as does my gluion interface (up to 66). However, I've never tried to control an analog synth with it. For starters the frequency at which the PWM operates would have to be above 20kHz. The gluion can do this, however at a reduced resolution of 10bits. Maybe this could be optimized to some extent by carefully selecting integrating capacitors, although this depends a bit on the desired update rate. In any case I haven't tested this, so I'd be reluctant to sell you a unit based on speculation. I hope I can get hands on an analog synth soon to give it a try - if you know someone in Berlin who'd like to bring one to my lab let me know....
      P.S. just found this: http://www.doepfer.de/mcv24.htm probably way easier.....
    • Feb 28 2006 | 8:59 pm
      that's right. i'm looking for the highest-resolution way to control an analog synth with max/msp. thanks for all the replies so far!
    • Feb 28 2006 | 9:05 pm
      Oops, yes it appears so. MidiTron does up to 20 PWM outputs with up to 7 bits resolution, though the rate goes down with more outputs enabled (there is a chart in the manual downloadable from http://miditron.com).
      Not sure of your application, but you might consider audio outputs to be hi-res D/A sources which can be driven directly from MSP.
    • Feb 28 2006 | 9:29 pm
      On 27 Feb 2006, at 22:39, matt wrote:
      > > Can someone shed some light on high-resolution (higher than MIDI or > 7 bits) interfaces between Max/MSP and analog control voltages? > Is there anything like this? Are there 14 bit MIDI to CV converters? >
      it has been reproted on this list that a Motu 828 has DC coupled outputs so you could go from MSP to analog out. I have no info about the resolution (number of bits).
      excerpt from the original posting
      On Jan 12, 2006, at 7:32 AM, Pierre Alexandre Tremblay wrote:
      > Hi list ! > > Probably less interesting than the new macs, but less speculating > as well! > > I remembered someone talking about generating Control Voltage out > of Max by regular audio converters, and people had ideas on some > machine who would do it and some not. > > http://www.synthesisters.com/hypermail/max-msp/Dec04/19244.h tml > > Since the thread ends abruptly without anyone actually giving a > reliable answer, I went down with a motu 828 mk1 and mk2 and > plugged them in an oscilloscope. I also tried the Powerbook output. > > So here are the result: > > Both the motu output DC without problem, at the same voltage than a > 440 cycle. The mk2 has a real +/- 5v, and the mk1 has +/- 3.2 v. > > The mac output does have an HPF, therefore is losing a lot of > voltage from 10Hz and lower. > > I thought it could be helpful to someone else. > > pa >
    • Feb 28 2006 | 9:33 pm
      ah, that's very helpful. i'll check my E-MU 1616m to see if it's outputs are DC coupled.
    • Feb 28 2006 | 9:38 pm
      perhaps, but only four outputs are 12bits, rest is 8bit... and you're stuck with midirate updates..
      Joost Rekveld ----------- http://www.lumen.nu/rekveld
      "The mystery of the world is the visible, not the invisible" (Oscar Wilde)
    • Feb 28 2006 | 9:48 pm
      How many channels do you need and how many have to be high-res? Usually you only need high-res for pitch control, while other parameters work fine with less resolution. The Doepfer box I suggested has a nice mix of 4 high-res + 20 low-res.
    • Feb 28 2006 | 9:53 pm
      i'd like as many hi-res as possible but the doepfer looks good. essentially i'd like a very high-res interface between my PC and my analog modular.
    • Feb 28 2006 | 10:05 pm
      In my experience, the problem using the 828 to generate CV has been a loss of linearity caused by impedence mis-matching. Making a very simple voltage following buffer with a cheap opamp for each output (or input) channel of your 828 should let you send sig~ out of your 828 with linear response.
    • Mar 01 2006 | 11:22 am
      Quote: cebec wrote on Tue, 28 February 2006 14:53 ---------------------------------------------------- > i'd like as many hi-res as possible but the doepfer looks good. > essentially i'd like a very high-res interface between my PC and my analog modular. > ----------------------------------------------------
      i can recommend doepfer as a great company. if you have any questions, subscribe yourself to the doepfer A100 yahoo list. dieter is up there himself and answers many questions, some other very knowledgeable people up there too, though I wouldn't expect them to have a lot of experience with max, but that doesn't seem necessary.