The auditory system of humanoid robots has recently gained significant attention in the research community. This system enables interaction with the surroundings via microphone arrays embodied into the robot. Typically, a single array topology is designed which may limit the performance of the auditory system. In a recent paper, a system with two array types has been studied: the first consists of sensors distributed over the robot's head, and the second is a body-mounted robomorphic array. These arrays have only been studied separately without exploiting their performance as a single array. In this work, a unified framework has been developed for the two arrays in the spherical harmonics domain, and an initial investigation of direction of arrival estimation (DOA) with the unified framework is presented. The simulation study shows that the unified framework outperforms DOA estimation with the individual arrays, mainly at the low frequency range.