Audi A4 B9 Facelift — Subwoofer Menu Activation (MIB3)

Your A4's subwoofer is already working — this activation gives you the hidden slider to actually dial it in.

€50

One-time · Permanent VIN-verified Same-day confirmation

What You Get

Audi A4 B9 Facelift models with Audi Sound System (PR-9VD) are limited to basic Bass and Treble controls from factory. The subwoofer plays the whole time you're driving, but its level cannot be adjusted independently anywhere in the MMI. This activation enables the hidden subwoofer menu, exposing a separate slider for the subwoofer so you can balance it against the main bass for a more controlled, tailored sound — all through a guided, VIN-specific OEM workflow inside RetroLab Pro, with no dealer visit, no remote coding session, and no manual scripts required.

How It Changes Behavior

From factorythe MMI Sound menu only offers Bass and Treble. The subwoofer is wired up and playing, but there's no way to dial it up or down — you're stuck with whatever balance Audi pre-mixed for the cabin.

After activationa dedicated Subwoofer slider appears next to Bass in the MMI Sound menu, letting you trim or boost the sub independently of the rest of the EQ until the cabin sounds the way you want it to.