October 18, 2019, 12:32:58 am
Welcome, Guest. Please login or register.
Did you miss your activation email
News:

Arturia Forums



Author Topic: Precise amount of frequency modulation with LFO (resolved)  (Read 327 times)

Franco1964

  • Newbie
  • Apprentice
  • *
  • Posts: 7
  • Karma: 0
Precise amount of frequency modulation with LFO (resolved)
« on: December 20, 2018, 07:51:50 pm »
Hi,

I'm trying to modulate the frequency of my analog signal by exactly 12 semitones (an octave) with the LFO (square wave). If I select the "Coarse" control at 12 steps, obtain an output signal that is, using "Unipolar" parameter in LFO, far less than an octave. If I use Bipolar, the modulation is more than an octave. Evidently, the range from maximum peak of LFO and zero is less than 1.

How can I resolve?

Maybe LFO is not the correct tool for obtain a precise amount of modulation?
« Last Edit: December 21, 2018, 05:59:43 pm by Franco1964 »

LBH

  • Hero Member
  • *****
  • Posts: 2.399
  • Karma: 50
Re: Precise amount of frequency modulation with LFO
« Reply #1 on: December 20, 2018, 08:48:13 pm »
A way to do it is setting a LFO modulation value for the Tune Coarse to positive 0.10.
When you use LFO Unipolar does'nt this give you one octave up from the note you play?
Be sure all LFO settings is correct so the tune does'nt move.

Also remember you have the Mod Quantizer to help set intervals.
« Last Edit: December 20, 2018, 08:54:49 pm by LBH »

Franco1964

  • Newbie
  • Apprentice
  • *
  • Posts: 7
  • Karma: 0
Re: Precise amount of frequency modulation with LFO
« Reply #2 on: December 21, 2018, 03:29:10 am »
A way to do it is setting a LFO modulation value for the Tune Coarse to positive 0.10.
When you use LFO Unipolar does'nt this give you one octave up from the note you play?
Be sure all LFO settings is correct so the tune does'nt move.

Also remember you have the Mod Quantizer to help set intervals.

No, the difference in pitch between the two sounds, if I use a parameter of 10 on Tune Coarse, is about 7 semitones (the double if I use Bipolar). And Mod Quantize doesn't work with intervals > 11 semitones.
« Last Edit: December 21, 2018, 03:39:26 am by Franco1964 »

LBH

  • Hero Member
  • *****
  • Posts: 2.399
  • Karma: 50
Re: Precise amount of frequency modulation with LFO
« Reply #3 on: December 21, 2018, 04:08:48 pm »
You are right, that the quantize does'nt work as exspected. Perhaps Arturia should have a look at this. I would consider this to be a bug.
When using quantize one should exspect, that you can set a lower value (at least down to 5 or 6) when having only 2 active steps set for a quantized octave. And Notes tha's unchecked should not sound, i assume.
You can set mod values between 10 and 14 and get an octave in Unipolar mode. A bit strange you can't, when it's not Unipolar.

But when i quantize with the value 0.10, then i do get an octaves in all cases.
(Do you have more modulations going on, that may affect the effect somehow? Or does the LFO work sometimes?)


When not using Unipolar, then i get an octave both up and down from the played note.Try the note before applying LFO and then with the LFO on. It can seem like it go 2 octave up but not down at all. But that's not the case, as you with a Square in my examples start hearing the sound one octave below the played note, because of the LFO modulation.
(Again do you have other modulation going on?)


I attach 4 example presets involving Quantize and/ or Unipolar. I have used LFO 2 with Phase set to 0.500.


Please attach a preset, if you still can't get it to work.


Franco1964

  • Newbie
  • Apprentice
  • *
  • Posts: 7
  • Karma: 0
Re: Precise amount of frequency modulation with LFO
« Reply #4 on: December 21, 2018, 05:59:17 pm »
Thanks LBH, all your samples work perfectly! The difference from my stuff is that you use the "general" coarse tune knob (the one at the far left). I used the coarse tune of the oscillator (analog), that evidently has a different parameter response.

EDIT: the mistake was mine: the range of coarse for single oscillator in 36 semitones. So, if I want an octave (circa), I must do a coarse tune of 17 with Unipolar. I hadn't understand that the parameter is in %, and not in value!

Thank you again!  ;)

Franco
« Last Edit: December 21, 2018, 07:04:55 pm by Franco1964 »

LBH

  • Hero Member
  • *****
  • Posts: 2.399
  • Karma: 50
Re: Precise amount of frequency modulation with LFO (resolved)
« Reply #5 on: December 21, 2018, 07:09:52 pm »
Hi Franco1964,

Your welcome.

Then we found out, why we had a difference between our results. Great.


But Arturia need to have a look at the Mod Quantize. That's not resolved.


If you use the Coarse for a single OSC in a Analog module, then it look like you shall use modulation values around 0-16-0.17, 0.33 and 0.50 for 1, 2 and 3 octaves.
I think first Octave is quite off, the second close enough, and the third correct with those numbers. But check it out yourself.

Also keep in mind, that you for OSC 2 and 3 in those modules also can modulate the fine tuning parameters too in some amount, with the same LFO. That can correct the last tuning.
« Last Edit: December 21, 2018, 07:19:01 pm by LBH »

 

Carbonate design by Bloc
SMF 2.0.13 | SMF © 2016, Simple Machines