The Acousonde™ is a newly designed miniature acoustic/ultrasonic recording tag incorporating several improvements over its predecessor, the Bioacoustic Probe. Design trade‐offs for its acoustic data paths targeted acquisition of both near and distant odontocete echolocation clicks with minimal distortion while preserving general‐purpose utility and low‐power operation. Two acoustic channels are available: a low‐power channel for long‐term recording of signals up to 9 kHz and a high‐frequency channel for signals up to 100 kHz. Each channel has its own dedicated hydrophone. For antialiasing, the low‐power channel uses an adjustable switched‐capacitor elliptic filter, while the high‐frequency channel uses a fixed‐frequency linear‐phase filter; both filters may be bypassed if raw acquisition is desired. “Ping‐pong” alternating sampling may be used to acquire samples from both channels concurrently, possibly to assess time‐of‐arrival differences between the two hydrophones. The controlling microprocessor, an ARM 9 with vector floating point accelerator, can digitally filter and downsample acoustic data during acquisition to reduce storage requirements. Other sensors include a 3D accelerometer, a 3D compass, a depth transducer, and a temperature monitor. Eight gigabytes of data storage are available, with data offload via a MicroUSB connector. Initial tests with captive animals are planned shortly. [Work supported by ONR.]