i have a circle and i want to increase the size parenting the size whit a value of the soundkey but having tottaly control of it...one of the things there appends its the circle increase whit rytmh but frome a little point to a big big circle i wish to have more control... how can i do this? thanks.
Alt+click the stopwatch to apply an expression. For more reference on how to learn expressions, examples and so on check the main AE forum. Anyway, in your case it's not necessary. Just set your output Ranges to "Custom" in the effects controls in Soundkeys, then dial in you minimum and maximum radius.