A buoy to record infrasonic and low-frequency sea-noise

A buoy has been designed to operate as long as nine months and tested to obtain infrasonic and low-frequency sea noise data in water depths exceeding 11,000 feet. The principal mechanical component is a spherical hull containing the control logic, amplifiers, record-only tape recorder and power supply. The useable acoustic frequency response is from 2 Hz to about 70 Hz; the low-frequency performance was attained using FM recording techniques. When deployed, 21 acoustic samples per day were recorded simultaneously from two hydrophones; each sample was 112 seconds long.