How Do Underwater Speakers Work? The Science Explained

Have you ever wondered how people can listen to music or announcements while swimming or diving? It’s all thanks to a fascinating device called an underwater speaker!

Underwater speakers are specially designed to transmit sound through water, which can be challenging due to water’s density and pressure. This can be done via bone conduction or radiating sound off the entire surface area of the pool.

In this article, we will explore the science behind how underwater speakers work, the different types available, and their practical applications. So, if you’re curious about how underwater speakers make it possible to enjoy audio entertainment in aquatic environments, read on!

Understanding Sound Waves

Underwater speakers work on the principle of sound waves traveling through water. Sound waves are created when vibrations compress and decompress water molecules, forming waves that travel in all directions from their source, similarly to ripples on the surface of a pond.

In air, sound waves vibrate the audio bones in our inner ear, which is called air conductivity hearing. However, when we’re underwater, flooding in the outer ear prevents these vibrations, leaving us with limited hearing ability (ever tried to have a conversation underwater?).

Underwater speakers work around this limitation by transmitting the sound waves directly through the water.

There are some key differences between how sound waves behave underwater compared to in air. For example, sound waves tend to travel faster and farther in water than in air due to water’s density and pressure. This can affect how sound is perceived when listening to underwater speakers.

Underwater speakers are designed to efficiently transmit sound waves through water, enhancing our ability to hear and enjoy music or announcements while submerged. By adapting to the unique properties of sound waves in water, underwater speakers are able to provide a unique and engaging listening experience.

What Do Underwater Speakers Sound Like?

Underwater speakers produce sound differently than traditional air-based speakers. In a quality underwater speaker, the sound radiates off the entire surface area of the speaker instead of from a focused point, creating a more immersive sound experience similar to a fine wooden instrument such as a cello or violin.

These speakers use piezoelectric transducers to generate sound. By applying an electrical signal to a piezoelectric material such as a crystal or ceramic, the material vibrates and produces sound. This technology allows for clear, resonant audio even when submerged in water.

Floating speakers are technically another type of underwater sound system. Encased in waterproof material and designed to float on the water’s surface, floating speakers are perfect for pool parties and other outdoor gatherings. These partially submerged speakers can achieve both resonance and clarity, providing an enjoyable listening experience above the surface (but not underwater).

Some underwater speakers, like Oceanears, even include a large bass speaker specifically designed for lower frequencies, making them suitable for marine research facilities to play sounds or music to underwater creatures like sharks, whales, and dolphins.

How Underwater Speakers Work

Underwater speakers work similarly to regular speakers, with one major difference: they must operate in a much denser medium – water. This calls for specialized technology and design to create clear, audible sound. There are two key elements to consider when understanding how underwater speakers work:


A transducer is a device that converts one form of energy into another. In the case of underwater speakers, the transducer is responsible for converting electrical energy into sound energy.

One type of underwater speaker uses electrostatic systems, which create an electrostatic field that causes a thin membrane to vibrate and produce sound.

The other type of underwater speaker is a more conventional approach, using speaker cones to create pressure waves in water. Since water is 773 times denser than air, the transducer must be specifically designed to handle the denser medium and create clear sound.

Encapsulation Materials

The second key element lies in the material used to protect and encapsulate the speaker components, ensuring they can operate safely while submerged in water. One solution is to use waterproof housing around the speaker. These housings are designed to keep the speaker components dry and allow for proper operation even when fully submerged.

Another material used for underwater speakers is polymers that are specifically designed to be water-resistant and cost-effective. These materials also ensure that the sound produced by the speaker can travel effectively through water without being distorted or weakened.

Types of Underwater Speakers

Bone Conduction Speakers

Bone conduction is a method used by some underwater speakers to transmit sound directly to the inner ear through the bones of the skull.

This technique bypasses the eardrum, allowing you to hear music or sound even when submerged in water. Bone conduction speakers typically have a small, pad-like device that rests on your head, sending vibrations to your inner ear.

One of the advantages of using bone conduction underwater speakers is that they don’t require you to wear earbuds or headphones that could fall out when swimming. These speakers can provide a comfortable and secure listening experience while you enjoy aquatic activities.

Piezoelectric Speakers

Piezoelectric underwater speakers are another common type found in pools or aquatic environments. These speakers utilize an electrical signal to vibrate a piezoelectric material, such as a crystal or ceramic, which generates sound waves. This design allows them to work effectively underwater, providing clear sound transmission.

By using a piezoelectric transducer, these speakers can radiate sound off their entire surface area, resulting in a more immersive listening experience. Regardless of the type of underwater speaker you choose, it is essential to ensure proper installation and safety precautions, such as using a ground fault circuit interrupter and an isolation transformer to prevent electrical hazards.

Applications of Underwater Speakers

Swimming Pools

Underwater speakers are a popular addition to swimming pools because they enhance the swimming experience by allowing swimmers to enjoy music while underwater.

In swimming pools, sound waves from underwater speakers travel fast and bounce off the pool’s bottom, sides, and water surface. This results in sound reaching the listener from all directions, providing an immersive audio experience.

Some real-world examples of underwater speakers being used are for synchronized swimming, at hotel pools, hot tubs, and private pools.

Marine Research

Underwater speakers also play a critical role in marine research. Researchers use these speakers to communicate with underwater sensors and transmit data between underwater and airborne devices. One such system, developed by MIT Media Lab researchers, uses a sonar signal directed at the water’s surface to cause tiny vibrations that correspond to binary data.

Underwater speakers in marine research applications often rely on piezoelectric transducers. These transducers use electrical signals to vibrate piezoelectric materials, such as quartz or ceramic, to create sound underwater.

Are Underwater Speakers Safe?

When it comes to using underwater speakers, safety should be a top priority. To enjoy these unique devices without compromising the safety of swimmers and the speaker system itself, there are several factors to consider.

First, make sure that the pool speakers you choose are specifically designed for underwater use. Underwater speakers are engineered to be water-resistant and safe for swimmers, so they won’t pose a risk of electrical shock when submerged.

Next, proper installation is crucial. As you know, water and electricity don’t mix. Ensure that you follow the manufacturer’s recommendations for installing the speakers or hire a professional to install it for you, as improper installation can result in poor sound quality, damage to the speaker, or even create a dangerous situation in the water.

Lastly, be mindful of the underwater noise levels. Prolonged exposure to loud sound levels can be harmful to you. Following best practices for underwater noise measurement and maintaining appropriate volume levels will help ensure a safe and enjoyable experience for swimmers and the surrounding environment.