Mixing from 12B to 3B

How to mix this transition

Because this is a parallel-key upper relationship with a significant tonal shift, treat the transition as a mini-breakdown moment rather than a blend. Bring in the new track during a phrase boundary — ideally after an 8 or 16-bar section in 12B — and use a 4–8 bar overlap to let both keys coexist before fully committing. EQ the incoming 3B track's mids and highs gently to avoid harshness during the overlap; the semitone proximity can create phasing if both tracks sit in the same frequency band. A kick swap or drum fill at the transition point will anchor the listener's ear to the new key and mask any harmonic ambiguity. Avoid dropping the new track's bass line too early — let the melody and drums establish 3B's gravity first.