Forums > MaxMSP

high-res interface between Max/MSP and analog CV

February 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?


February 28, 2006 | 7:43 am

Hi Matt,

The Miditron can handle analogue in with a range of 0-16383 using Pitch
bend.
See http://www.eroktronix.com.


February 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.

Eric

********************************************
* MidiTron MIDI to Real World Interface *
* Now available from http://eroktronix.com *
* Only $149 *
********************************************


February 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….

Sukandar

P.S. just found this: http://www.doepfer.de/mcv24.htm
probably way easier…..


February 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!


February 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.

Eric


February 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
>


February 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.


February 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)

——————————————-


February 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.

Sukandar


February 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.


February 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.

b


March 1, 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.


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