The room impulse response (RIR) and measures derived from it have been a powerful tool for room characterization. Traditionally, these measures are based on time domain characteristics like reverberation time or clarity. By recoding a group of RIRs with microphone arrays, one can add the spatial dimension to the RIR. Spherical microphone arrays are of special interest since they can give equal weight to all directions. In this paper, we explore an adaptive cardioid beampattern algorithm for its suitability as a tool for the spatial analysis of RIRs. The algorithm uses the spherical harmonic base patterns (“Eigenbeams”) of a spherical microphone array to form and steer a cardioid beampattern. The steering is automatically adjusted to minimize the output power in a specific time region. Due to the cardioid beampatterns sharp null in the beampattern, an adaptive cardioid algorithm can provide detailed spatial information on reflections as a function of time for impulse responses.