The acoustic comfort
What is the acoustic comfort?
The acoustic comfort is the well being perceived by a user during an activity inside a sound field. As regards the acoustic quality of the environments dedicated to listening to the words, it is necessary to ensure no interference and a good reception and understandability.
How to get it?
Ensuring the absence of noise means reducing any background noise disturbing the sound produced by the speaker. The good reception is linked to the presence of a sufficient sound level in the environment and to the perception of directed and reflected sound wawes. The disturbances, such internal or external sound sources disturbing the soundscape, should be removed or reduced.
Dissipation’s mechanisms of the acoustic energy
The dissipation’s mechanism of the acoustic energy inside the materials are:
1. Absorption for porosity
A materiali s defined porous when the relationship between empty space and total volume is high. The porosity allows to dissipate sound energy transforming it into heat because of the vibration of air particles in the pores.
2. Resonance cavity
The presence of cavities inside the material ease the air vibration, and also in this case, due to the friction occurs sound absorption. In is also possible to fill the cavity with sound-absorber material to obtain the desired value of sound damping.
3. Membrane resonance
The presence of vibrating panels allows to transform part of the sound energy into mechanical energy, therefore favoring the absorption.
The importance of the acoustic insulation
The Law 447/1995 regulate the acoustic pollution and the DPM 5 December 1997 determines the passive acoustic requirements of buildings. All the structures have to guarantee a minimum performance of soundproofing. These limits vary depending on the use of the room and the source of the noise. The website Edilportale.com offers some causes of reflection about the topic: soundproofing what to choose?
The acoustic insulation with materials in fiber (as rock wool or glass wool) takes place thanking the absorption for porosity and it is a solution recommended for high frequencies. These materials are economically favorable and are usually used to soundproof perimeter walls.
Materials of plant origin
Material of plant origin (as cork or the wood fibers) use their porosity to offer an excellent soundproofing and anti-vibration. They are used to reduce air noises, treading noises and for the side walls.
Artificial materials are usually generated by the the work processo of oil, havea low cost and offer a quite good acoustic insulation. Although easily usable, thanks to a quite simple process of laying, but they have to be handled with care as they could cause problems in case of fire.
Soundproof materials (such for example the rubber) reflect the sound in the environment from which it originates. They have excellent soundproofing capability and a low thickness. These materials are often used with phono-absorbing materials to offer the best soundproofing.