Howtosignalprocessing
How are hydrophones made?
Most hydrophones are made from a piezoelectric material. This material produces small electrical charges when exposed to pressure changes. The pressure changes associated with a sound wave can be detected by a piezoelectric element.
How far can a hydrophone detect sound?
Using an underwater microphone called a hydrophone, a second boat stationed 900 miles away successfully detected the sounds. Subsequent tests picked up the signal at a distance of 3,000 miles.
Do hydrophones work in air?
A hydrophone can detect airborne sounds, but will be insensitive because it is designed to match the acoustic impedance of water, a denser fluid than air. Sound travels 4.3 times faster in water than in air, and a sound wave in water exerts a pressure 60 times that exerted by a wave of the same amplitude in air.
