Hydrophones: Digi-tell me about it!

April 2, 2020

Did you know that hydrophones have been around for over 100 years? The first hydrophones were developed in 1914 to be used during WW1 to help submarine crews avoid collision with icebergs. A lot has changed since 1914; the technology has advanced and the sensors have become exceptionally more precise and reliable, but at their core, modern hydrophones share much in common with their 20th century predecessors.

Basic analog piezoelectric module

Most modern hydrophones are ceramic based, as is the icListen. These hydrophones are made up of a few essential pieces, the most important being a proprietary ceramic material called piezoelectric compound. This piece of ceramic is what converts acoustic energy into electric energy, giving the hydrophone its ability to listen. The other hydrophone components include pre-amplifiers for improved sound quality and water-tight housing, usually a rubber boot, to ensure the electronics don’t get wet.

A hydrophones accuracy depends on the quality of its piezoelectric element. This element will flex and restrict when changes in pressure are detected. It is the flexing and restricting that generates the electrical signals that become your ocean sound data. The use of piezoelectric compounds spans from the first hydrophones developed, all the way through to todays modern tools, where it remains widely used.

Deployment of an icListen as a long-term recorder

In analog hydrophones, it wasn’t possible to listen in real-time as the hydrophone was operating, instead, the sensor had to be deployed, then retrieved, the data downloaded and then processed by specialized computer programs. During this process it is not uncommon to make a mistake, either by incorrectly configuring your hydrophone, deploying the hydrophone in a loud area, even choosing the incorrect mooring. All of these mistakes are easy to make and often undetectable until the data has been processed and evaluated. Takes months and months to process

The advent of a smart hydrophone with in-situ processing changed that. The icListen was the world’s first smart hydrophone. The goal was to allow users to collect, process, and listen to ocean sound data in real-time with simplified tools. The result has been accurate and reliable data from tools that users can communicate with even while deployed. Users can retrieve real-time data in a number of different ways either by using cables, radio, iridium or even wifi to view and listen.

Smart hydrophones have improved the quality and success of underwater recording and data streaming; however, many hydrophones today still function as analog sensors which take time to process and analyse the data. As computer chips get more powerful and AI is used in real-time processing, Smart Hydrophones like the icListen can give you information that help with real time decisions, for example, real-time detection of marine mammals during seismic surveying and marine construction.

Sophisticated tools such as the icListen are recommended for any project that requires high quality, accurate data. If decision making using real-time listening and processed data are your goals, the icListen is the only tool on the market able to provide both along with high-quality signal processing.



Ocean Sonics designs and manufactures the icListen Smart Hydrophone and are trusted world leaders in underwater listening. icListen users can be found across nearly every maritime industry including, but not limited to environmental monitoring, renewable energy, security, and scientific research.


Glossary of terms:

Smart hydrophone: A digital all in one instrument with the ability to collect and process data in real-time (icListen)

Digital hydrophone: A hydrophone where collected data is digitized at the source, making data more accessible, smaller and easier to work with. Digital hydrophones use analog sensors with built-in translation facilities

Analog hydrophone: A traditional hydrophone, data transmission is limited by size

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