Are CV inputs normalled to knobs for all devices?

[Mikro93]

Hi all,

I looked around on the forum and couldn’t find a definitive answer to that question: How do CV inputs relate to parameters and knob values?

My understanding is that PARAMETER_A is both related to knob A and CV input A, and that both signals are added internally when getting parameter values. As such, there would be no way to get a value from CV input A that would be connected to a different parameter than knob A, correct?

That would explain why some of the Lich patches use Audio In L to track V/oct, as it would interfere with knob values.

FWIW I’m currently experimenting with C++ patches and a Wizard.

[Mikro93]

Replying to myself with this message:

CV ranges for Wizard, Alchemist, Magus?

hi gc3! On the Wizard, the outputs are 0-3.3V. The inputs are attenuated by the corresponding knob, so if you plug into CV A you can control the level with Knob A. The inputs are protected so you can safely send them anything from -10V to +10V. Voltage Ranges (Wizard) CV In: 0-10V with attenuation/gain 0x to 2x CV Out: 0-3.3V Trigger in: 0-10V, threshold 0.8V Trigger out: 0V off, 3.3V on Audio Out: 4.5VPP Impedance (Wizard) Audio In: 100k Audio Out: 22 Ohm CV In: 15k CV Out: 1k Trig…

@mars states that knobs should act as attenuators for CV input signals on the Wizard, and I feel like it is not the behaviour I encountered last time I tried to wrap my head around it. I’ll try again tonight.

[antisvin]

You won’t get any comments from Martin here, he’s moved to other things a while ago, unfortunately.

@Mikro93

How do CV inputs relate to parameters and knob values?

It’s a question of hardware design really.

I know that in newer Rebeltech hardware CV inputs and knobs are measured separately and merged in firmware. That’s what makes it possible to control attenuation amount digitally. I’m not really sure if that’s the case for all of their devices.

There are some devices that can run OWL firmware where voltage is mixed as a single signal (i.e. Daisy Patch). I wouldn’t be surprised if some older Rebeltech devices do the same as it’s often good enough to be usable.

@Mikro93

That would explain why some of the Lich patches use Audio In L to track V/oct

There are several reasons why usually V/Oct is measured from codec input:

1. It gives much higher precision and sampling rate
2. There’s established calibration measurement procedure for this
3. Some patches don’t need both audio inputs (i.e. a typical VCO which takes V/Oct and some FM modulation signal)

Generally this has been the default behavior for OWL patches, only in some recent modules V/Oct from CV input got used. Witch patches needed it because it used AC coupled audio input. And Oneiroi needed it as it processed stereo audio.

[Mikro93]

Thank you!

@antisvin

I know that in newer Rebeltech hardware CV inputs and knobs are measured separately and merged in firmware. That’s what makes it possible to control attenuation amount digitally. I’m not really sure if that’s the case for all of their devices.

My question is, in that case: from a C++ standpoint, is there a way to get the CV value separately from the knob value? I see all these PARAMETER_AA etc. in the enum, are these only internal/MIDI parameters?

@antisvin

Generally this has been the default behavior for OWL patches, only in some recent modules V/Oct from CV input got used. Witch patches needed it because it used AC coupled audio input. And Oneiroi needed it as it processed stereo audio.

Gotcha. I’ll look into the code for Witch, but at first glance, I couldn’t find a patch where V/oct was implemented from a CV input (I see FM, which comes from an audio input, which is AC coupled as you said)