kicksville
sigh....I have always wondered why we've never had the S-curve option on clip fades and envelope automation. All the other kids have it - why can't we? 
Well, not all the other kids have it...as to SONAR, maybe it hasn't been submitted as a feature request.
I use the S curve in Vegas all the time for overall fades in both video and audio tracks, but the method presented in the tip is more flexible because it's easy to "weight" the fade by moving the middle node. While I don't need to weight an overall master song fade often, it's very helpful with clip automation - like when you want something to linger with a slow fade, then leave quickly; or jump down rapidly to a level, then fade out slowly from there.
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