Easiest way is to record white/pink noise as a waveform, normalize and then use volume automation, some chorus/flanger/reverb and eq automation, that makes it very easy to just add a clip, set the length of the clip to how long you want it and add volume automation rising until the crescendo.
Just record 8 bars of white/pink noise and set the clip length as needed, it takes way to much effort to adjust the adsr of a synth to match the length you need every time.
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