Reverberation time is a term that is commonly used in an acoustics context. It refers to the duration of the echo. Sound will continue to be heard for a while after its source has shut off. This is due to the sound waves being reflected off the different surfaces of the room. Reverberation time is determined by how long the sound can be heard after the source has gone quiet. If the reverberation time is too long, phonemes in words are mixed and speech becomes difficult to follow. As a consequence, people tend to raise their voice or turn up the volume on the television, for example. This results in an even noisier sound environment.
Reverberation time is significantly affected by the size and shape of the room as well as the amount and placement of the soundproofing material. Unless the number of sound absorbing surfaces is sufficient, the reverberation time will increase in proportion to the amount of wall surface. The acoustics in a room can be improved and the reverberation time shortened by increasing soundproofing material and carefully considering its placement.
Hard surfaces that reflect sound do not dampen or absorb it much. Room acoustics should be balanced in a manner where hard surfaces should always have a sound absorbing surface opposite to them.
Absorption or sound damping classes
The sound damping or absorption classes are A, B, C, D and E pursuant to standard EN ISO 11654. Sound damping capability is measured at frequencies of 200–5,000 Hz. Products in absorption class A have the best damping capability. Correspondingly, products in absorption class E offer the least amount of damping. Soften’s interior panels with acoustic filling are in the best possible sound damping or absorption class A (EN ISO 11654). Interior panels without the separate acoustic filling are in absorption class C (EN ISO 11654).
Health effects of noise
Acoustics can greatly affect people’s mental and physical well-being. Research shows that noise is the second-largest contributor to public health problems, surpassed only by microparticles.
Noisy rooms make normal communication difficult. They are tiring and stressful and straining on the memory, thinking and the processing and regulation of emotions. The detrimental effects of noise are seen as sleeping disorders, difficulties in concentration and learning, and functional disorders of the heart and blood circulation. In a worst case, noise can be the cause of reduced hearing and hearing damage.
Importance of acoustics in day nurseries and schools
Noisy environments are stressful for the children and personnel alike. Teaching situations are mainly based on natural language communication – speaking and listening supported by good acoustics. The audibility and comprehensibility of speech are particularly important for day nurseries with a view to the child’s speech development. Adults know how to form complete words or sentences from individual syllables, but children are not as far developed as that. This makes a good sound environment especially important.
A poor sound environment will also directly affect the well-being of the teaching personnel. Poor audibility causes a strain on the voice, which will break easily. Continued stress may even cause problems with the vocal cords. Noise also generates general fatigue and stress.
Research proves that a comfortable and calm learning environment promotes calm behaviour and moderate speech volumes, result in more peaceful schoolwork. Abnormal noises stand out more thereby, which improves overall safety.
Acoustics and well-being at work
Acoustics are an important part of ergonomics. Noise, and noisy speech in particular, is the most common problem in indoor office environments. Acoustics become particularly important in workspaces and office rooms, as they have a key effect on the mental and physical well-being of the employees. Among other things, good acoustics simplify communication and make focusing on work easier, improve performance and work efficiency, reduce stress and increase worker comfort.
Popular open plan offices and flexible workstations set specific requirements in terms of room acoustics. Workers in open plan offices are often distracted by background noise, outdoor noise and, in particular, hearing other people speak and being able to distinguish words in their speech. Good acoustics in an open plan office are characterised by speech not being distinguishable between the workstations.
Noise level can be affected by adding soundproofing material in the room and placing it correctly. As the noise level is reduced, people will no longer consider it necessary to raise their voice and will start speaking more softly than before. This results in a further reduction of background noise and improved acoustics in the working environment.
The acoustics of a space should be viewed as a whole. The final room acoustics are affected by the following factors, for example: the amount of damping material, any high walls dividing the workstations and any hanging elements. A masking noise that can cover up speech is also a good way to supplement the overall solution.
Some 10% of the working-age population are estimated to have some degree of hearing defect. Special attention should be paid to the working conditions of an employee with a hearing aid, for example. The hearing aid will amplify all the sounds in the environment, including the background noise, which can make speech difficult to follow, for example. In this case, the importance of acoustics becomes essential in the workspace design.
Effect of home acoustics on living comfort
Lately, more and more attention has been paid to improving the sound conditions of the living environment. Home interior design currently favours tall rooms, large window surfaces and hard walls and floors, which further increase reverberation issues. The lack of soft interior materials caused by this trend results in insufficient sound damping, which in turn emphasises echoes inside the home. Open space solutions are also challenging in terms of acoustics.
Different hobby spaces can also be taken into account by means of acoustics planning. Home theatres, music rooms or musical instruments may create the need to improve acoustics in order to achieve a pleasant sound environment. Staircases are also an obvious place for placing soundproofing material in the home in order to prevent sounds from crossing between the different floors.
At home, you also need to pay attention to the personal needs of the inhabitants, while also taking into account comfort and interior design aspects. Acoustics should be considered already during the architect’s planning stages in order to achieve a holistic solution. This is usually also cheaper and more functional than trying to solve the problems afterwards.