Can't get an accurate semitone automation

[Freden]

Hey guys,

I'm trying to automate the semitone knob of my instance of Xfer Serum on one of my MIDI melodies.
The problem I'm currently having is the following :
When I've created the automation envelope for that particular knob, the automation lane is shown but I don't know why I'm unable to place the point accurately to have, say, two semitones higher on a particular note.

Is there a way to subdivide the automation grid lane in 12 steps so that the semitones accurately correspond to the value of the grid ?
(I tried to affect a value by using the "set value to point" option on the point however the value is between 0 and 1, if you divide 1 by 12 it gives something like 0.08333333 which makes it harsh for an accurate value).
Or maybe I'm doing something wrong?

Thank you for your time and answers !

Freden

[ashcat_lt]

If the envelope is in Write or Latch mode you should be able to place the playback cursor where you want it and then just set the parameter in the plugin itself. It'll place a point in the envelope corresponding to that exact value. No?

[Freden]

Hello ashcat_It,

Thank you for your quick reply !
Yes, it does work like that, I've just tried. Thank you for the tip, I don't cease to learn new things on this amazing DAW thanks to the community ! )))
Is it not possible to do it directly in the automation lane without using latch/write mode? (I've spent the afternoon trying to figure it out via the official user guide, other web sources and by myself).

I tried what you suggested, it works perfectly, but still I don't understand the value of the point which is 0.602 for 2 semitones.
Also, it's in latch mode, so when I move other knobs on my synth plugin (it's not the final sound so I try things here and there), it creates a lot of new automation lanes with all the knobs I moved which is not very convenient in this particular situation.

Thank you again !

Freden

[Xenakios]

Originally Posted by Freden

but still I don't understand the value of the point which is

The plugins can implement arbitrary mappings between the GUI/user value and the normalized (0.0 to 1.0) value that is dealt with by the host. (For example in its automation envelopes.) There is unfortunately no standard way to get the normalized number from the GUI/user value. (At least with VST2 plugins.)

Many plugin parameters will just use a linear mapping (which can be reversed with simple math), but also exponential, logarithmic and more exotic mappings are possible.

[alanofoz]

I'm probably missing something with your calculations - I'm not sure why you're dividing 1 by 12. The relationship of two notes a semitone apart (equal temperament) is the twelfth root of 2 i.e. 1.05946309.

So starting with A 440, A# would be 440 * 1.05946309 = 466.16.

etc.

Please ignore if we're talking at cross purposes.

[Xenakios]

Originally Posted by alanofoz

I'm not sure why you're dividing 1 by 12.

This is about converting semitones into the normalized range 0.0 to 1.0 that hosts use internally in their automation envelopes and so on. So dividing 1.0 by 12 is a reasonable starting point, but doesn't apparently work with the particular parameter in the particular plugin under discussion.

If the parameter uses a simple linear mapping, the formula to get the normalized value from the GUI/user value is :

normalizedvalue = 1.0/(maxvalue-minvalue)*(value-minvalue)

[ashcat_lt]

Originally Posted by Freden

...it's in latch mode, so when I move other knobs on my synth plugin (it's not the final sound so I try things here and there), it creates a lot of new automation lanes...

Put back into Trim/Read before you turn other knobs!

You could just figure out what value it writes for a given setting, make a list or whatever, and just enter those manually. Maybe you'll see some pattern in the process, but otherwise you just look it up when you need it.

It is kind of frustrating that the envelope values don't match the GUI except in certain circumstances, but I think that's either outside the scope of the VST standard or not well implemented in most plugs.

[mpl]

You can call a script which quantize envelope point values to semitones (Serum specific).
Vertical snap quantize realized in Reapack/mpl_Snap points values for selected envelope.lua, but you have to change how much steps your envelope contains (disclaimer: only for linear mapped values).
Edit: it will be an action in QuantizeTool 2.