Thanks Koby, I will give it a try. So the principle is: if you want to turn 'off' an expression you set it up so you can do the 'opposite'?

This is the error:
[attachment=0]expressionError.jpg[/attachment]

Thanks for replying Koby My expression now looks like this but returns an error: Audio = linear(thisComp.layer("Audio Amplitude").effect("Both Channels")("Slider"), 0, 30, 1, 4) SldTransf = thisComp.layer("control").effect("SldTransf")("Slider&q...

Hi http://www.vertigo.co.uk/cow/expressionHelp.jpg As you can see from the image I have a letter 'O' being animated to keyframes from an audio layer via a couple of effects; Warp and Transform. My aim is; at a certain point I want the influence from the effects to fade down so that the letter appear...