Sound and Water: How We Hear Music Underwater
Listening to music underwater is a surprisingly different experience from listening to the same music in the air.
The notes are the same. The instruments are the same. The recording is the same.
But the environment through which the sound travels has completely changed.
Water modifies the way acoustic waves propagate and also changes the way the human auditory system receives and interprets them.
This is what makes underwater music such a distinctive sensory experience — and why transmitting high-quality sound into a swimming pool requires technology specifically designed for underwater acoustics.
What Is Sound?
Sound is a mechanical vibration that travels through a medium.
That medium can be:
air;
water;
metal;
wood;
glass;
or many other materials.
A sound source creates vibrations that produce changes in pressure.
These pressure variations travel through the surrounding medium as sound waves until they reach a receiver — such as the human ear.
Without a medium capable of transmitting these vibrations, sound cannot propagate.
Does Sound Travel Differently in Water?
Yes.
The physical properties of water and air are very different, so sound does not behave in the same way in both environments.
In air, the speed of sound is approximately 340 meters per second.
In seawater, it is approximately 1,500 meters per second, although the exact value varies depending on factors such as temperature, pressure and salinity.
Sound therefore travels more than four times faster through water than through air.
This difference has major consequences for underwater listening.
Why Does Sound Travel Faster Underwater?
Sound waves propagate by transmitting vibrations between particles.
Because water molecules are arranged much more closely together than air molecules, vibrations can be transmitted rapidly through the medium.
However, sound propagation underwater is influenced by several environmental factors.
Temperature
Changes in water temperature affect the speed at which sound travels.
Pressure and Depth
As depth increases, pressure changes and can influence sound propagation.
Salinity
In marine environments, salt concentration also affects the speed of sound.
Frequency
Low-frequency sounds generally travel farther underwater than high-frequency sounds.
These properties explain why underwater acoustics are used extensively in fields such as oceanography, marine biology, sonar and underwater communication.
How Do Humans Hear Underwater?
The human auditory system evolved primarily for hearing in air.
Under normal conditions, sound waves enter the external ear canal, vibrate the eardrum and are transmitted through the middle ear toward the inner ear.
Underwater, the situation changes.
Water surrounds the head and ears, while the difference between the acoustic properties of the body and the surrounding medium becomes smaller.
As a result, underwater hearing involves a different combination of transmission mechanisms.
Research has investigated both conventional auditory pathways and vibration transmission through the tissues and bones of the head. The exact contribution of these mechanisms can vary according to frequency and listening conditions.
Why Is It Difficult to Locate Sound Underwater?
One of the most noticeable differences when listening underwater is the difficulty in determining exactly where a sound is coming from.
On land, the brain uses very small differences in the time and intensity at which a sound reaches each ear.
These differences help us determine whether a sound comes from the left, right, front or back.
Underwater, sound travels much faster.
The timing differences between the two ears are therefore considerably reduced, while other acoustic cues used for localization are also altered.
Scientific studies have shown that human directional hearing is significantly less precise underwater.
This helps explain why underwater music can feel unusually enveloping.
Instead of clearly identifying a conventional left or right speaker, listeners may perceive the sound as surrounding them.
Why Does Music Feel Different Underwater?
Underwater listening is not simply conventional listening at a different location.
Several factors change simultaneously.
Sound Reaches the Listener Differently
The acoustic wave travels through water rather than air.
Direction Becomes Less Obvious
The listener may find it difficult to identify exactly where the music originates.
The Body Is Immersed in the Acoustic Medium
Unlike a conventional stereo system, where sound travels through the surrounding air, an underwater listener is physically immersed in the same medium through which the acoustic waves propagate.
External Noise Is Reduced
When the ears are submerged, much of the airborne environment disappears.
The listener enters a very different acoustic space.
Together, these characteristics can create a particularly immersive listening experience.
Can We Feel Sound Underwater?
Sound is vibration.
When a person is immersed in water containing acoustic waves, those waves interact with the submerged body as well as the auditory system.
Lower frequencies in particular may contribute to the physical sensation of vibration.
This does not mean that sound produces the same effect as a conventional physical massage.
However, it helps explain why underwater listening is sometimes described as a more bodily or enveloping musical experience.
At AquaMusic, this sensory approach has contributed to the concept of Musical Massage: an underwater music experience built around immersion, sound and relaxation.
What Happens to Music Frequencies Underwater?
A musical recording contains a wide range of frequencies.
Bass instruments occupy lower frequencies, while voices, guitars, percussion and harmonics extend into the midrange and high frequencies.
Underwater, these frequencies do not all behave in exactly the same way.
In natural aquatic environments, lower-frequency sounds can generally propagate over greater distances than higher-frequency sounds.
For music reproduction, this means that an underwater speaker must be designed to reproduce a sufficiently broad and balanced frequency range.
Simply generating noise underwater is easy.
Reproducing music with clarity, detail and dynamics is considerably more demanding.
Why Can’t You Use a Regular Speaker Underwater?
A conventional loudspeaker is designed to move air.
Its cone, suspension, enclosure and electrical components are engineered specifically for an airborne environment.
Immersing a standard speaker would not only damage it, but also prevent it from operating as intended.
An underwater speaker must instead be designed to transfer acoustic energy efficiently into water.
Waterproof Construction
The components must withstand continuous exposure to water.
Suitable Acoustic Transducer
The system must be capable of generating vibrations efficiently within an aquatic environment.
Electrical Safety
Pool installations require appropriate equipment and installation practices designed for wet environments.
Frequency Response
The speaker should reproduce music rather than simply generate audible underwater signals.
This is where specialized underwater audio technology becomes essential.
How Does an Underwater Speaker Work?
An underwater speaker — sometimes referred to as an underwater transducer — converts an electrical audio signal into mechanical vibrations.
These vibrations generate pressure waves in the surrounding water.
The principle is similar to a conventional loudspeaker, but the acoustic and mechanical design is adapted to the properties of water rather than air.
When connected to a compatible amplifier and music source, the underwater speaker allows swimmers to hear music while their ears are submerged.
Where Is Underwater Sound Used?
Underwater acoustics have applications far beyond recreational swimming pools.
Swimming Pools
Music can accompany recreational swimming, aquatic classes and immersive experiences.
Synchronized Swimming
Underwater speakers allow athletes to follow music and timing while submerged.
Spas and Wellness Centers
Underwater music can contribute to relaxation and sensory experiences.
Thermal and Rehabilitation Pools
Aquatic environments are also being explored for applications involving relaxation, rehabilitation and music-based interventions.
Artistic Performances
Musicians, choreographers and artists have used underwater sound to create performances that could not exist in a conventional concert environment.
Marine Science
Underwater acoustics are essential for studying marine environments, animals and human-generated ocean noise.
Sound, Voice and Water
The relationship between sound and water is not limited to recorded music.
Voice is also vibration.
The original research and workshops that inspired AquaMusic explored connections between:
aquatic listening;
voice;
movement;
improvisation;
language;
artistic expression.
Immersion creates a different sensory environment in which conventional references to sound and space are altered.
For artists, singers and performers, this can provide an unusual field for experimentation.
Water as Part of the Musical Experience
In a conventional sound system, the room influences the way music is heard.
Walls reflect sound.
Furniture absorbs certain frequencies.
Room dimensions create resonances.
In underwater music, the water itself becomes the acoustic environment.
The listener is no longer standing outside that environment.
They are inside it.
This is perhaps the most important difference between conventional audio and underwater audio.
The water is not simply where the music is being played.
It becomes part of the listening experience.
More Than 30 Years of Underwater Sound at AquaMusic
AquaMusic has been developing underwater sound systems since the early 1990s.
Over the years, this work has led to applications in:
private swimming pools;
public pools;
synchronized swimming;
spas;
thermal facilities;
physiotherapy;
wellness;
underwater concerts;
and experimental aquatic listening.
The objective remains the same:
to reproduce music underwater with enough clarity and quality to create a genuine musical experience.
Understanding the relationship between sound and water is at the heart of that challenge.
Frequently Asked Questions About Sound Underwater
Does Sound Travel Faster in Water Than in Air?
Yes.
Sound travels at approximately 1,500 meters per second in seawater compared with around 340 meters per second in air.
The exact speed in water depends on factors such as temperature, pressure and salinity.
Can Humans Hear Music Underwater?
Yes.
Humans can hear sound while submerged, although the mechanisms and perception differ from conventional hearing in air.
A dedicated underwater speaker can transmit music directly through the water.
Why Is It Hard to Tell Where Sound Comes From Underwater?
Sound reaches both ears with much smaller timing differences underwater than in air.
As a result, the auditory system receives fewer of the directional cues it normally uses to locate a sound source.
Is Sound Louder Underwater?
Air and underwater sound levels cannot be directly compared simply by looking at their decibel values because underwater acoustics use different reference pressures.
A sound measured at the same numerical decibel value in air and water does not represent the same physical sound intensity.
Can You Use a Normal Speaker Underwater?
No.
Conventional speakers are designed for air and are generally neither waterproof nor acoustically optimized for underwater operation.
A purpose-built underwater speaker or transducer is required.
Why Does Underwater Music Feel Immersive?
Several factors contribute: the listener is surrounded by the acoustic medium, directional localization becomes more difficult, airborne environmental sounds are reduced, and vibrations are transmitted through the water surrounding the body.
What Equipment Is Needed to Play Music Underwater?
A typical system includes:
one or more underwater speakers;
a compatible amplifier;
an audio source;
and an installation appropriate for the pool and intended use.
The exact configuration depends on pool size, speaker placement and the type of listening experience required.
