echo sounder, seismometer, geophone, sonde, sonar, dropsonde, telemeter, transmitter, gyrocompass, fluorometer, spectrographic, resonant cavity, transducer, spectrograms, birdcall, bioacoustics, electroencephalograph, submersible, minisub, toadfish, seafloor, retroreflector, oceanographic, gradiometer, klystron, seismograph, inclinometer, radiosonde, sounders, airglow, buoys, inertial navigation system, bathysphere, bathyscaph, narwhals, voltmeter, humpback whale, gulper, bathyscaphe, underwater, microelectrode, radiometer, anechoic chamber, goniometer, lanternfish, reflectometer, remus, altimeters, manometer, snailfish, sonification, sensor, dolphins, vocalizations, radiotelephone, stroboscope, microswitch, cardiograph, strain gage, marum, lazarette, dipole antenna, archerfish, resonators, lavalier, condenser microphone, inferior colliculus, brachiopods, directional antenna, geomagnetism, electrodes, finback, whale, subantarctic, electromagnet, otoliths, lavaliere, eegs, spectroscopic analysis, birdsongs, porpoises, spectroscope, microphones, bathymetry, bilge pump, strain gauge, mossbauer, homing device, seabed, davit, paramecia, dipole, elint, bolometer, annunciator, pulser, sextants, cetacean, otolith, omnidirectional antenna, deimos, echolocation, microphone, hydrophones, loudspeaker, accelerometer, analyser, anemometer, camera, dosimeter, receiver, calorimeter, dynamometer, interferometer, magnetometer, photometer, probe, resonator, thermistor