How is a reduction in decibels (dB) and sound level perceived?
Understanding how sound levels change and how a reduction in decibels (dB) is perceived is essential for evaluating the effectiveness of soundproofing and sound-absorbing measures. Decibels are a logarithmic unit, which means that changes in sound level do not occur linearly. A reduction of, for example, 10 dB does not mean that the sound is reduced by 10 percent – it is instead perceived as if the volume has been cut in half.
In environments such as offices, schools, restaurants, conference rooms, and homes, it is important to understand how dB changes affect the perception of sound in order to create a comfortable and functional acoustic setting. Here, we explain how we perceive sound reduction, the difference between soundproofing and sound absorption, and how to create an optimal sound environment.
How does a decibel reduction affect the sound experience?
The effect of a sound reduction depends on both the physical change in sound energy and how the human ear interprets the sound.
- A reduction of 3 dB means that the physical sound energy is halved, but the difference is perceived as relatively small to our ears.
- A reduction of 10 dB is perceived as the sound being halved in volume, even though the actual energy has decreased by about 90 percent.
- At a 20 dB reduction the sound is perceived as being reduced to one-fourth of its original strength.
How different types of sound are affected by dB reduction
How a sound reduction is perceived also depends on the nature of the sound.
- Smooth and low-frequency sounds (such as ventilation systems or motor noise) require a greater dB reduction to be noticeable.
- Sudden and high-frequency sounds (such as sharp voices or metallic noises) feel more subdued even with a small reduction in volume.
In environments where background noise is a challenge, such as open offices and restaurants, even a small dB reduction can make a big difference in acoustic comfort.
Sound absorption and soundproofing – What is the difference?
Creating a pleasant and effective sound environment often requires a combination of sound absorption and soundproofing.
Sound absorption
Reduces sound reflections within a room using materials such as acoustic panels, carpets, and curtains. These help reduce reverberation and create a more comfortable acoustic environment.
Soundproofing
Focuses on blocking sound from transferring between rooms or from external noise sources. This involves using high-density materials such as soundproof doors, windows, walls, and floors.
Examples of how soundproofing and sound absorption are used together
- In office environments, sound-absorbing screens and fabric-covered furniture reduce echo and background noise. At the same time, soundproof doors and windows prevent sound from entering from outside.
- In restaurants, acoustic panels and sound-absorbing ceilings reduce the noise level, while heavy curtains and dampening flooring materials contribute to improved acoustic comfort.
- In recording studios and home theaters, both soundproofing and sound absorption are used to block external noise and enhance sound quality within the room.
The environment and room characteristics affect the sound experience
How much a dB reduction affects the sound experience also depends on the size of the room and its acoustic characteristics.
- In large, open spaces such as conference rooms or restaurants, even a relatively small reduction in sound level can make a significant difference. Reduced reflections from walls and ceilings contribute to a more pleasant atmosphere.
- In small rooms with hard surfaces, such as kitchens or bathrooms, the sound level can still be high despite a dB reduction. This is because the sound reflects between surfaces and creates long reverberation.
How to adapt sound control to the room
To manage different types of spaces, the right combination of sound-absorbing and soundproofing measures is required.
- Acoustic ceilings and wall panels reduce sound reflections in larger rooms with a lot of reverberation.
- Sound-absorbing furniture and textiles improve the sound environment in offices and homes.
- Heavy curtains and rugs reduce sound reflections in smaller rooms with hard surfaces.
By adapting the sound measures to the room’s characteristics, you can create a more pleasant and comfortable sound environment.
How to create an optimal sound environment
To effectively reduce sound levels and create a pleasant sound environment, the measures need to be adapted to the specific needs of the room.
Do you want to reduce reverberation and improve speech intelligibility?
Use sound absorbers in strategic locations, such as ceilings and walls.
Do you need to protect against external noise?
Invest in soundproof doors, windows, and wall materials.
Do you work in an environment with high background noise?
Combine sound-absorbing screens and acoustic solutions to create a better working environment.
By using a balanced combination of soundproofing and sound absorption, you can create an optimal sound environment tailored to your needs.
Understand and control sound levels effectively
Understanding how sound reduction in dB is perceived is key to creating a pleasant and functional sound environment. The most important insights include:
The sound experience changes logarithmically
A reduction of 10 dB is perceived as a halving of the sound.
Different types of sound require different actions
Low-frequency sounds are harder to dampen than high-frequency ones.
Sound absorption and soundproofing complement each other
For best results, both methods should be used together.
The room’s acoustics affect the sound experience
Adapt sound measures to the room’s size and materials.