sound locator; acoustic detector; hydrophone
A device for detecting and locating sound sources, used in military, maritime, and scientific contexts. 聴音機 is the more common spelling for equipment.
A sound locator was used to detect the submarine.
This hydrophone can pick up underwater sounds.
ソナー (sonar) is a more modern and common term for sound navigation and ranging, while 聴音機 is an older or more specific term for a passive listening device.
水中聴音器 explicitly means underwater listening device (hydrophone), whereas 聴音機 can refer to both air and underwater sound locators.
Standard kanji spelling for a sound-detection device.
Alternate kanji spelling; 器 suggests an instrument or tool.
Compound of 聴音 (listening to sound) + 機/器 (machine/device). The exact historical origin is uncertain, but it likely emerged in early 20th-century military and maritime technology contexts.