SESSION 3: INTERFACING LOUDSPEAKER AND ROOM Adaptive Bass Control - The ABC room adaptation system Jan Abildgaard Pedersen Bang & Olufsen A/S, Struer, Denmark This paper presents a system for adapting a loudspeaker to its position and to the acoustic properties of the listening room: the ABC room adaptation system. Adaptive Bass Control (ABC) measures the acoustic radiation resistance seen by the bass drive unit and calculates the coefficients of a digital IIR filter, which is inserted in the signal path before the power amplifier. This enables ABC to provide a room adaptation, which is globally valid throughout the listening room, i.e., all listening positions benefit from this system. DSP is used to measure the radiation resistance, calculate the filter target, and filter coefficients and to implement the IIR filters.