In this paper we describe a system for passive acoustic sound source localization in 3D using a distributed microphone array. By distributing the microphones into smallscale and large-scale arrays we can exploit array processing algorithms that use near-field and far-field properties of the sound source with respect to the array. The microphones on the smallscale device are sampled using a single, simultaneously sampling analog to digital converter which results in time synchronization between these microphone channels up to a small fraction of the signal's phase. The large-scale array consists of multiple smallscale devices and can be deployed over a much larger capture volume. We create the distributed microphone arrays in a manner that is scale-free with regard to the amount of microphones in the system, the capture volume, the type of sound and the type of sensors/microphones. In this paper we describe the hardware topology, the localization algorithms and the obtained results.