Room acoustics is a complex field with a multitude of clearly defined technical terms. Understanding the planning, evaluation, and optimization of acoustic measures requires being able to correctly classify this technical terminology. In our acoustics glossary, you will find precise and technically sound definitions of key terms from the areas of room acoustics, sound absorption, reverberation, speech intelligibility, and sound insulation.
Acoustics Lexicon
Terms and definitions related to room acoustics
A clear and practical explanation of acoustic principles, as well as a concrete determination of the acoustic requirements for your rooms, can be found on our acoustics calculation page. There you will learn how an objective assessment of room acoustics is carried out based on room data and usage scenarios, and which measures are effective in specifically meeting the acoustic requirements.
Acoustics Lexicon
Acoustics dictionary - terms and definitions related to room acoustics
Room acoustics is a complex field with a multitude of clearly defined technical terms. Understanding the planning, evaluation, and optimization of acoustic measures requires being able to correctly classify this technical terminology. In our acoustics glossary, you will find precise and technically sound definitions of key terms from the areas of room acoustics, sound absorption, reverberation, speech intelligibility, and sound insulation.
A clear and practical explanation of acoustic principles, as well as a concrete determination of the acoustic requirements for your rooms, can be found on our acoustics calculation page. There you will learn how an objective assessment of room acoustics is carried out based on room data and usage scenarios, and which measures are effective in specifically meeting the acoustic requirements.
Reverberation ("t" time and calculation)
- ... is the important room acoustic parameter.
- ... is the time it takes for the sound level in the room to drop by 60 decibels.
- ... can be easily measured
- ...or can be roughly estimated by sighting. Source: WC Sabine
Sound attenuation = sound absorption (“a”)
- Room acoustic parameter
- Impediment of sound propagation by absorption of airborne sound (physical definition)
- The sound is not reflected by the surface, but absorbed.
- Unpleasant reverberation is reduced through absorption.
- Goal: To modify the room sound in order to improve room acoustics and create optimal listening conditions.
Sound insulation
- Building acoustics parameter
- Improve acoustic separation between rooms
Frequency ranges (“Hz”)
- Frequency = The frequency of vibrations. A low number of vibrations produces low tones; the more vibrations, the higher the tones.
- Room acoustics: 63 – 8,000 Hz
- Hearing range of the human ear: 16 – 20,000 Hz
- Bauakustik: 100 – 3,150 Hz
Sound pressure level dB (A)
- Sound level is a logarithmic quantity used to describe the intensity of a sound event. In everyday language, sound level usually refers to volume or noise intensity.
- We perceive an increase in level of 10 dB as roughly a doubling of the loudness. Examples:
- Kindergartens: approx. 80-85 dB
- quiet conversation 40 - 60 dB
- heavy road traffic 70 - 90 dB
Standards / Guidelines / Recommendations
- DIN 4109: Sound insulation in building construction
- Workplace Ordinance and Accident Prevention Regulations on Noise § 15
Recommendations only:
- DIN 18041: Audibility in small to medium-sized rooms
- DIN 18032: Audibability in sports halls – Halls and rooms for sports and multi-purpose use
- VDI 2058: Assessment of noise in the workplace taking into account different activities
- VDI 2569: Sound insulation and acoustic design in the office
Evaluation of the sound absorption capacity of materials
- a: Sound absorption coefficient: Values between 0 (complete reflection) and 1 (complete absorption). Absorption varies depending on the frequency.
- as: Frequency-dependent sound absorption coefficient: Absorption values for 18 frequencies between 100Hz and 5000Hz
- aw: weighted / rated sound absorption coefficient: measure of sound absorption capacity: a value between 0 and 1. For complete reflection, a=0; for complete absorption, a=1.
