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Understanding the spatial and temporal structure of ambient noise is a critical factor for estimating the performance of active and passive sonar systems. This is especially true in warm shallow waters where snapping shrimp dominate the ambient noise spectrum over 6 octaves. Snapping shrimp sources can be problematic for active sonar, but are key sources for Ambient Noise Imaging systems. The impulsive nature of snapping shrimp sounds permits the use of a sparse array to beamform on the source, providing each of several channels is sampled at a sufficiently high rate, perhaps 200 kSa/s or higher. If four channels are used to sample hydrophones placed at the vertices of a tetrahedral array in shallow water, the resulting 3-D aperture can be used to estimate the source direction in azimuth and elevation. In general, the altitude of the array will be known, and if the sources are snapping shrimp, they must lie on or very near the seabed. Thus the range may also be deduced and the spatial/temporal source distribution mapped. A second motivation for designing a compact high-frequency data acquisition system was to study dolphin echolocation. The system we have designed and built is based on COTS components.