How to : PureData OSC/LFO with Lich’s CV out

WalkTheDog 2021-01-27 17:06:42 UTC #1

Hi !

I try to understand how to output signal from an pure data OSC to the Lich’s CV output...
Can somebody explain it to me please ?
Thank you !

antisvin 2021-01-27 17:19:05 UTC #2

Have a look at puredata documents and Lich template

WalkTheDog 2021-01-27 18:08:04 UTC #3

Thanks, but i already did.

The thing that block me is, that i do not understand how to feed the CV output from the amplitude object of of the osc.
I tryed with [snapshot~] to convert audio signal into « data number » but that not seems to work, maybe it need to be « updated » with a clock [metro], i just don’t get it à the moment...

mars 2021-01-28 00:07:32 UTC #4

I'm not a Pd developer but if you are creating an LFO with an [osc~] object then it is probably better practice to use control rate objects to feed a control rate output.

Having said that, [snapshot~] should work, given the following caveats:
- make sure the output is in the 0 to 1 range, not -1 to 1 like audio signals
- make sure the osc~ is not running too fast

Since you're only sending one value each block (every 64 samples), for anything more than around 100 Hz you are going to see a lot of stepping in the output.

An example can be found in the Fascination Machine patches, e.g.
https://www.rebeltech.org/patch-library/patch/Fascination_I
Look at the abstraction in chronos.pd, which implements a tempo synched dual LFO based on our Eurorack module Chronos.
(There are also abstractions for Tonic, Stoicheia, Phoreo and other useful bits and pieces)

WalkTheDog 2021-01-28 07:29:06 UTC #5

Yea thanks !!
Yesterday i finally manage to make it work ! 🤣 And honnestly i don’t understand why i didn’t suceed sooner !
I guess that some time, when you do too much pure data, you need to sleep a litle bit ! 🤣🤣🤣

Thank you very mutch for the reference of the chonos patch, It will be very usefull !!! 🤠

WalkTheDog 2021-01-30 14:11:59 UTC #6

Ok, let’s make a clean explication on how to do it: (for people from the futur)

-Create osc object [osc~]

-Create amplitude object [*~ ]

-Connect the left outlet of the oscillator into the left inlet of the amplitude object.

-Add a message box, or à fader, or anything that can output a value to the left inlet of the osc to control the frequency.

-Add a message box, or à fader, or anything that can output a value to the right inlet of the amp object to control the volume. (Preferably between 0 and 1)

-scale the output to be between 0 and 1 (because LFO are in -1 and +1) with : [/~ 2] and [+~ 0.5]. (if the amp is in 0 and 1)

-Create a [snapshot~] object to transform audio into number.

-Connect the LFO/OSC output via [+~ 0.5] to the [snapshot~] input.

-Create a [metro] object to create a refresh rate to the snapshot fonction, and add a number to define the refresh cycle, for exemple: [metro 100] (100 millisecond rate)

-Connect the output of the metro to the input of the snapshot in the same input as the LFO/OSC.

-Connect the output of the snapshot to the inlet of the LICH’s cv output object ! ( [s CV_OUT_1 @owl F] )

-Enjoy your new LFO !

Allways remember to right clik every object you create and have a look into the « help » menu to learn how it really work !