Acoustic knowledge
Understanding Room Acoustics
Table of contents
1. Introduction: Why is room acoustics important?
2. Basics of Acoustics
2.1. The physics of sound
2.2. Acoustic measurements
3. Typical acoustic problems and their causes
3.1. Reverberation and poor speech intelligibility
3.2. Noise pollution and fatigue
3.3. Uneven sound distribution
4. Modern acoustic solutions
4.1. Acoustic absorbers
4.2. Diffusers
4.3. Acoustic zoning
5. Conclusion: Scientifically based room acoustics for a better quality of life
1. Introduction: Why is room acoustics important?
The acoustics of a room not only affect our perception of speech and music, but also our well-being, our concentration and even our health. Poor acoustics can lead to stress, fatigue and communication problems.
Targeted measures to optimize acoustics are particularly important in offices, restaurants, schools, concert halls, studios and living spaces. But how do room acoustics actually work?
2. Basics of Acoustics
2.1. The physics of sound
Sound spreads as a wave and hits different materials, which affect it in different ways. The most important acoustic effects are:
✔ Absorption: Sound energy is absorbed by special materials such as foams, fabrics or wood fibers and converted into heat. This reduces reverberation.
✔ Reflection: Hard surfaces such as glass or concrete reflect sound, which can lead to prolonged reverberation and unwanted echoes.
✔ Diffusion: Structured surfaces scatter the sound in different directions to achieve an even sound distribution in the room.
Good room acoustics are based on a targeted interaction of these three factors.
2.2. Acoustic measurements
To understand and optimize acoustics, various metrics are used.
Reverberation time (RT60): The time it takes for a sound to decay by 60 dB after the sound source is switched off. The optimal reverberation time depends on the use of the room:
• Offices & classrooms: approx. 0.5–0.8 seconds
• Restaurants & hotels: approx. 0.6–1.0 seconds
• Music rooms & concert halls: approx. 1.5–2.5 seconds
Speech intelligibility (STI – Speech Transmission Index): Assesses how well speech can be understood in a room. An STI value of over 0.75 is considered excellent.
Sound pressure level (dB): The volume of noise is measured in decibels. For comparison:
• Whisper: approx. 30 dB
• Office environment: approx. 55 dB
• Road traffic: approx. 80 dB
3. Typical acoustic problems and their causes
3.1. Reverberation and poor speech intelligibility
❌ Problem: Conversations are difficult to understand, music sounds muddy or too loud.
⚠ Cause: Lack of absorption surfaces, large hard surfaces, too few furniture or curtains.
Solution:
• Absorber with high absorption coefficient (α ≥ 0.85 for medium frequencies)
• Targeted placement of wall and ceiling elements to reduce reverberation
3.2. Noise pollution and fatigue
❌ Problem: Noise level is too high, conversations and work noises disturb concentration.
⚠ Cause: Open-plan rooms with many reflective surfaces.
Solution:
• Sound-absorbing materials with high NRC (Noise Reduction Coefficient) values
• Zoning through acoustic partitions and absorbent furniture
3.3. Uneven sound distribution
❌ Problem: Certain frequencies are amplified or suppressed, the sound is unbalanced.
⚠ Cause: Unfavorable room geometry, no diffusers, too much or too little absorption.
Solution:
• Diffusers for sound dispersion
• Targeted combination of absorbers, diffusers and reflective elements
4. Modern acoustic solutions
4.1. Acoustic absorbers: Reduce reverberation & improve speech intelligibility
According to DIN 18041, recommended reverberation times are prescribed depending on the use of the room. There are various types of absorbers to achieve these.
• Wall absorbers: Effective against reflections and disturbing reverberation
• Ceiling sails & baffles: Particularly suitable for high rooms with strong reverberation
• Bass absorber: Especially for low frequencies in studios or home cinemas
4.2. Diffusers: scattering sound in a targeted manner
In music rooms, concert halls and studios, diffusers help to distribute the sound evenly throughout the room. They prevent flutter echoes and create a pleasant sound image.
4.3. Acoustic zoning: structuring rooms acoustically
It is especially important to create acoustic zones in offices, restaurants and open-plan areas.
• Partitions & room dividers: Create quiet areas and prevent sound transmission
• Acoustic furniture: combination of functional design and sound absorption
• Individually printed acoustic elements: Aesthetic solutions that fit seamlessly into the room design
5. Conclusion: Scientifically based room acoustics for a better quality of life
Good room acoustics are more than just noise protection - they create a pleasant environment for concentration, communication and sound quality. Through the targeted use of absorption, reflection and diffusion, rooms can be optimally adapted to their use.
Whether it’s an office, restaurant, recording studio or event room – with the right acoustic solutions, rooms not only become audibly more pleasant, but also noticeably more pleasant.
Would you like to find out more about the right acoustics for your rooms? We'll be happy to advise you!