Some AI generators, Suno V6 in particular, do not hold a track steady from start to finish. The end comes out louder, darker and narrower than the beginning: the bass folds toward mono, the air thins out, the stereo field closes in. Mastering then locks that drift in, because a master is made from the whole track at once. Since 4.45.0, Preparation measures the drift and takes it out before anything else happens.
What it does
Smart Preparation compares the repeated sections of your track with each other: a second chorus against the first, a last verse against the first. Where the later section has drifted, it brings its level, tone and stereo width gently back toward the earlier one. It is a slow, section-sized correction, not an effect; nothing in the arrangement changes. Tracks that do not drift pass through untouched, and short tracks (under about two and a half minutes) do not have enough repeated material to compare, so they pass through unchanged as well. It cannot rescue a weak generation, but it removes the drift.
Where it runs
It runs first in the SpectralForge correction chain, before the artifact repairs, and it is included in every run that prepares the file: Preparation, Analysis + Preparation and Auto-Master. There is nothing to switch on. The run report shows the measurement before and after, so you can see what was moved and by how much.
The measurements behind it
The drift was measured across 52 tracks and confirmed by ear before the correction was built. The two articles that document it: Suno V6 runs out of steam shows the drift itself, and Build it to hold explains what Smart Preparation does about it and what a prompt can do before the track is ever rendered.