Documentation on automation curve combination?

Hi, I am looking for documentation on how multiple automation curves are combined. From what I have found in this forum, the combination can be additive, maximum, multiply, … all depending on what is being automated.

I am currently trying to use two parameters to control the ‘speed’ parameter of the Audiowind effect. The default for ‘speed’ seems to be either sum or max. What I want is: parameter A is supposed to set the maximum speed, parameter B is supposed to reduce this value, ideally through multiplication.

This is probably possible by automating a parameter that in turn controls ‘speed’, but I can’t seem to find any documentation on the curve combination modes on either the Audiowind effect or parameter automations. Any pointers?

This is a complex question, because how automation curves are combined depends on the property being automated. In the case of the speed parameter of the Audiowind plug-in effect, the value after automation is the mean of all values to which the property is set by the automation curves on that property.

Taking the average of the values from all curves on the same property is the default behavior that most properties use - but there are a lot of properties, and plenty of exceptions:

  • If a property is measured in dB (a category which includes every track, send, bus, and instrument volume control in FMOD Studio, the wet/dry level properties of a number of effects, and a number of other properties), the values applied by automation curves are added, unless at least one of them is -oo, in which case the final value us -oo. (Naturally, if the property can’t be set to -oo, that last caveat doesn’t apply.)
  • The pan direction, stereo separation, stereo axis and height blend properties are summed.
  • The cutoff value of a highpass effect, instrument start offset, the ratio property of the compressor effect, the depth and mix properties of the chorus effect, the feedback property of the delay effect, the extent property of a track panner, and the spawn total and spawn rate of a scatterer instrument all use whichever automation curve value is highest.
  • The cutoff value of a lowpass effect, the threshold property of a compressor effect, and the high cut property of a reverb effect all use whichever automation curve value is the lowest.
  • The intensity property of a snapshot multiples all the values assigned to that property by automation.
  • Most other properties use the average of all properties applied by automation.

As you can see, there’s no simple general rule - but each property usually uses a resolution method that makes sense for that specific property.

The speed property of the Audiowind plug-in instrument follows the default behavior of using the average of all values.

Thank you :slight_smile: That is indeed complex.

So if I added an automation to a parameter, the values would be averaged as well?

Have you considered making the combination behavior configurable? That would certainly make automations more flexible and also make the default behavior for each property explicit.

That’s correct.

Not until you suggested it just now. I’ll add the suggestion to our tracker.

Thanks! :slight_smile: