Hydrophones

Underwater Acoustics

Beneath the surface of the water, the world sounds completely different. In environments where light quickly fades and visibility is limited, sound becomes the primary means of perception, analysis and communication. It is through acoustic waves that we can explore the oceans, listen to the behaviour of marine animals, monitor the impact of human activities or assess the quality of natural and artificial aquatic environments.

Underwater acoustics is the science that studies the propagation of sound in liquids, and translates into technologies that are fundamental for numerous applications: from scientific research on the behaviour of cetaceans to the assessment of anthropogenic noise in marine protected areas; from the detection of leaks in submerged pipelines to the recording of immersive sounds for documentaries and art installations.

To operate in these contexts, precise, robust and reliable instruments are required. The main ones are hydrophones, devices similar to microphones but designed to work in water, even at great depths. Coupled with recording systems and analysis software, hydrophones allow capturing and studying vibrations and sounds that would otherwise be inaccessible to the human ear.

What are hydrophones?

Hydrophones are instruments designed to detect sounds and vibrations in liquids, just as microphones do in air. They use piezoelectric sensors that transform acoustic waves into electrical signals, allowing even the faintest underwater sounds to be recorded, from a few Hz up to over 150 kHz (even MHz in industrial and medical applications).

They are essential instruments for those working in marine research, environmental monitoring, industrial control or underwater audio-video production.

How do they work

A hydrophone generally consists of:

A piezoelectric sensor (or several combined sensors).
A waterproof and resistant coating (PU, epoxy or ceramic) to operate even at depth.
An interface or preamplifier to improve the signal and adapt it to various recording systems.

Depending on the application, a complete recording system may also include:

Broadband recorders.
USB interfaces.
Software for underwater sound analysis.
Cables, filters, power supply or battery boxes.

Why underwater acoustics is crucial today

In a world where the ocean covers over 70% of the Earth’s surface, understanding what happens underwater is essential. Yet, unlike the terrestrial environment, the underwater world is still largely unexplored: here, sound is the primary vehicle for communication, perception and monitoring. For this reason, underwater acoustics is today one of the most powerful tools available to researchers, engineers, biologists, environmentalists, and sound professionals.

Underwater sounds tell complex stories:

they reveal the presence of migrating cetaceans,
measure the noise levels of shipyards and underwater infrastructures,
identify leaks in pipelines or variations in pressure,
enable immersive audio experiences in installations and documentary films,
and are essential for assessing the acoustic impact of human activities on the marine ecosystem.

Acoustic analysis makes it possible not only to record sounds but also to measure their intensity, frequency, and variability over time. Calibrated systems can detect noise with scientific precision, even in ultra-low or high-frequency bands, providing reliable data for environmental studies, impact regulations, and technical reports.

Whether you are a researcher, technician, artist or simply curious about the underwater world, underwater acoustics offers a unique gateway to what the eye cannot see, but the ear can hear.

From basic systems to high-precision calibrated instruments, we offer a complete range of hydrophones and underwater recording solutions, selected to suit every need, budget and operating context.

With years of experience and collaborations with research institutions, universities, companies and international organisations, NAUTA scientific is your point of reference for acoustics in aquatic environments.

If you are unsure which system to choose, if you are planning an experiment, or if you want a tailor-made solution, please do not hesitate to contact us:

we will help you find the right technology to hear even where silence seems to reign.

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Human-based classification of acoustic signals in your recordings can be far more efficient. We coded some procedures and helpers to guide your efforts.