Make the Audio Bus effects adjustable with Animations and/or Tweens

[HVukman]

At the present state you cannot change audio effects while running Godot. See: https://imgur.com/a/HXRix5x
There are no key symbols and you cannot tween the values, since they are not node paths. See this code snippet:

# taking the first effect from the audio bus
var effect_0:AudioEffectPitchShift=AudioServer.get_bus_effect(0,0)

# error: argument should be node path but is float
tween.tween_property(effect_0,effect_0.pitch_scale, 0.9,1)
	
#error: argument is null_value
tween.tween_property(effect_0,"pitch_scale", 0.9,1)

You can make a new AudioEffect resource and tween the values, but then you have to add the effect to the bus again.

[AThousandShips]

You should be able to do this with a MethodTweener no?

The fact that it says that it's a null is a bit strange, are you sure you're getting the right effect? You've added an image of a AudioEffectDistortion but your code says AudioEffectPitchShift?

[Calinou]

You can access the AudioServer singleton from a script to modify various effects at run-time in a script. Use Tween's low-level interpolation methods to interpolate values when calling methods on the AudioEffect instances stored in the audio bus (the values returned by AudioServer).