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LFO's
stuartdavis
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PostPosted: Tue Oct 11, 2011 2:17 am reply with quote
We have been asked about creating LFO's in Studio Units, so I will attempt to describe a possible solution here.

To create a simple LFO for a plugin parameter, you just need to create an SU effect patch containing an SU transform with the following equation:

freq;amp;
lfo=sin(2*PI*BLOCK_TIME*freq)*0.5*amp+0.5

This will generate a parameter called lfo that varies sinusoidally with an amplitude of amp and a frequency of freq. If you double-click on the SU transform in the editor, the three parameters freq, amp and lfo will be shown in a new tab. You can now set freq and amp and watch lfo modulate. The parameter names lfo, freq and amp are completely arbitrary. You can change lfo to be the name of a parameter in another VST and then connect the parameter output (green) of the SU transform to the parameter input of another VST, which will then have this particular parameter enslaved to your LFO.
^ Joined: 31 Mar 2006  Member: #103321  
DJTreeno
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PostPosted: Tue Oct 11, 2011 3:44 am reply with quote
Hi, thanks for the answer to my question.
But why change of parametre "freq" lead to distortion of a wave.
It is visible on SU scope.
^ Joined: 01 Nov 2007  Member: #164462  
stuartdavis
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PostPosted: Tue Oct 11, 2011 4:09 am reply with quote
This is because changing the frequency has the unwanted effect of changing the phase of the LFO. I can't think of an easy way to make freq smoothly variable with the current set of SU modules.

It would probably make more sense for Studio Units to provide an LFO module. I will add a 'new feature requests' thread to the forum and put this at the top of the list. Thanks.
^ Joined: 31 Mar 2006  Member: #103321  
DJTreeno
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PostPosted: Tue Oct 11, 2011 4:15 am reply with quote
And to you thanks for a prompt reply!
Please make good LFO.
With impatience I will wait!
^ Joined: 01 Nov 2007  Member: #164462  
DJTreeno
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PostPosted: Wed Oct 12, 2011 12:22 am reply with quote
Please prompt as to transform a signal from tone generator to parameter. Afterwards to assign it on any knob.
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stuartdavis
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PostPosted: Wed Oct 12, 2011 12:56 am reply with quote
The following SU transform equation will do that for you:

~1;knob=$rms

where knob is the name of the parameter you want to control - this will be set to the Root Mean Squared value of the audio input.

Or as an alternative:

~1;knob=$peak

will set the parameter knob to the peak value of the audio input.
^ Joined: 31 Mar 2006  Member: #103321  
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