When a sound wave comes into contact with an absorbent material, one portion of the energy is reflected, another is absorbed into the material and a third passes through it. The sound absorption coefficient is the ratio of absorbed sound energy to incident sound energy and depends on the frequency.
What is an acoustic panel?
Acoustic panels correct the sound reverberation inside a closed space. In addition to their remarkable ability to absorb noise pollution, they combine both function and style!
Sound absorption refers to when a sound wave touches a soft, malleable or porous material and is completely or partially absorbed. The absorbed sound energy is transformed into heat. If the sound wave touches a hard object and is reflected, this is sound reflection.
Sound absorption influences how sound is perceived by users of a room. It controls the ambient noise level, prevents echo and its aftereffects, and increases speech intelligibility. The quality of a room’s sound absorption is determined by how the room is configured and the types of materials in it. Sound absorption prevents reverberation and echo from being produced. Reverberation and echo are by-products of the reflection of sound, at repeated intervals, off of surfaces and objects in the room.
The reverberation time of a room is the time required for the sound pressure to decay to one one-thousandth of its initial value. This is equivalent to a 60 dB reduction in sound volume. The echo effect depends on the absorption surface of the room and on the volume, and can vary according to the frequency. Perception of acoustic comfort in a closed space is directly related to a standardized rate of reverberation based on how the room is used. Reverberation time is counted in seconds. The Sabine absorption coefficient is used for absorbed reverberation. Following the result of our assessment, we will provide you with a proposal including materials and installation, as applicable.
In informal situations, speakers can be a distraction to each other as the sound volume is the same throughout the room. To be heard, each person starts to speak louder and louder until everyone is yelling. This is the "Cocktail Effect", the results of which can generate sound levels over 90 dBA, especially in restaurants and daycare centres. This level of sound has been observed and documented to cause irreversible hearing damage to individuals who are regularly exposed to it.
The clarity of a voice or of speech is defined by the quality of the words transferred to the listeners. In a reverberating room with distracting background noise, it can be difficult to hear what is said.
Loudness refers to the volume at which we perceive a sound. In a reverberant room, the perceived noise is much higher than in a room with sufficient absorption.
A sound level decreases as the distance from the source of the sound increases. The design of the room and absorbent materials (shape, furnishings, surface finishes, etc.) influences the speed at which the sound level decreases with distance from the source.
AUDITORY PERCEPTION – EAR SENSITIVITY – HEARING DAMAGE
Hearing sensitivity varies from one person to the next. It also depends on the ranges of frequency being considered. The ear has been shown to be most sensitive to frequencies between 250 and 4,000 Hz, which is the range in which we find the sounds in our everyday lives and in language. At an equal volume, a very low-pitched sound will seem quieter than a medium-pitched sound.
When an individual begins to experience hearing impairment, the first symptoms are trouble hearing high-pitched sounds and difficulty hearing conversations in noisy environments, followed by in all circumstances. Prolonged exposure to noise can cause irreversible hearing damage. New legislation has been adopted in recent years to prescribe a maximum sound level for daily exposure. Previously 90 dBA, the limit is now 85 dBA for an eight-hour period.
These levels are within the audible frequency range. The prescribed levels for infrasound and ultrasound frequencies have not yet been clearly established. For comparison, the maximum allowable level for certain concerts and clubs is set at 105 dBA, which would not be permitted for longer than 3 minutes in the workplace.
Even if a sound level is not sufficient to create hearing damage, there is still a risk of stress induced by noise exposure. This stress can lead to sleep problems, anxiety and even cardiovascular problems.
Sound-absorbing products are made from porous materials and have technical characteristics that allow them to absorb sound waves, correcting internal acoustic issues such as reverberation.
Panels made from compressed fibreglass, compressed volcanic mineral wool and various acoustic foams are high-performance products for closed spaces of any dimension. They can also be customized to integrate into any décor. They are an effective solution for offices, conference rooms, banks, company lobbies, movie theatres, concert venues and restaurants.
Baffles are high-performance suspended panels, each with its own suspension system, used in large spaces such as gymnasiums, arenas, churches, industrial factories, mall food courts and any other medium or large enclosed space.
Sound-absorbing materials must be directly exposed to the acoustic radiation. They can be secured or held in place on, for example, surfaces or structures, in perforated trays or on expanded metal.