Exponential curve on fader for Soft Synth LFO

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fknfade
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Posts: 3
Joined: 20 Nov 2013 14:40

Exponential curve on fader for Soft Synth LFO

Post by fknfade »

Hi there, I'm trying to make a Mu device template for the Arturia CS-80V2. I have everything mapped out and controlling the soft synth inside live just fine. But I want to mirror the values being displayed from my soft synth into my Mu device controller. The first one I'm tackling is the LFO1 for OSC1. The range goes exponentially from 0.01hz - 50.0hz but my Mu fader is sending a linear 0.00 - 1.00 value via OSC. I came up with a formula for this using an excel chart using this sample data:

x=.00 y=0.01
x=.10 y=0.13
x=.20 y=0.25
x=.30 y=0.62
x=.40 y=1.00
x=.50 y=2.50
x=.60 y=4.00
x=.70 y=14.5
x=.80 y=25.0
x=.90 y=37.5
x=1.00 y=50.0

The resulting formula: y = 0.0374e7.8864x
What I put into Fader --> Properties --> Value=0.0374*exp(7.8864*x)

The graph is somewhat close but I'm wondering how some of you would approach the problem. I'm not very good at math so this is the extent of my knowledge. Any help is greatly appreciated Thank you!
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Screen Shot 2013-11-20 at 7.30.03 AM.png
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Macciza
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Posts: 1315
Joined: 07 Dec 2011 04:57
Location: Sydney, Australia.

Re: Exponential curve on fader for Soft Synth LFO

Post by Macciza »

Hi
I think part of the problem is that it may not be an exponential function being used. Your series plot seems to have quite linear sections . .
Also remember that even though you are using 0-1 over OSC that the actual data being represented is MIDI as 0-127 . ..

Finally check out how arrays work and notice that it will interpolate between values . . .
So make an array of those values array = {0.01, etc , 50} and index into it with your x val times number of values - array[x*10]

See if that helps
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fknfade
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Posts: 3
Joined: 20 Nov 2013 14:40

Re: Exponential curve on fader for Soft Synth LFO

Post by fknfade »

Thank you thank you thank you!
The array function totally worked!

I'm not sure if it's getting mapped to 0-127 since i'm using abletons configure tool and not midi learn. In the screenshot below i put all available parameters at .50, then when i checked a knob it said 0.000 and the GUI showed it as being right in the middle. I would think that if it was getting interpreted as 0-127 that the knob wouldn't be in the middle.
I'd love your insight on this.

Thanks again!
fknfade
Newbie
Posts: 3
Joined: 20 Nov 2013 14:40

Re: Exponential curve on fader for Soft Synth LFO

Post by fknfade »

oops here's the screenshot:
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Softcore
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Posts: 1613
Joined: 04 Nov 2012 08:34

Re: Exponential curve on fader for Soft Synth LFO

Post by Softcore »

You realize of course that Ableton Live is ONLY capable of showing the first 128 parameters of the synth....

IS the parameter displayed in the image actually anywhere inside the parameters on the bottom? I dont see it.

edit to add: Live's native midi mapping also uses 0 - 127 range, dont worry about that!
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