An apparatus includes an amplifier having an input. An interface has inputs and an output. The interface is configured to: invert each bit of a value received at a first input of the interface to produce an inverted value; and provide the inverted value at the output. A processor has an input coupled the output of the interface, has first output coupled to a second input of the interface, and has a second output coupled to the input of the amplifier. The processor is configured to determine whether to set an adjustable gain setting of an audio processing block to the inverted value.