The difference between sound insulation & sound absorption
For the engineering of a building or structure, risks and dangers are carefully assessed. Some of the risks being assessed are e.g. fire risks, explosion risks, and excessive noise risks. The latter risk can be mitigated by achieving a good and comfortable sound level for the protection of the hearing of personnel and wildlife.
Architectural acoustics provide several benefits within and outside structures. Next to decreasing the risk of hearing loss, architectural acoustics allow conversations to be heard and increases personnel’s concentration and productivity.
Sound engineering generally takes compartments within structures into consideration. Each compartment or area needs another approach of soundproofing. For offshore applications, rooms next to rooms with heavy machinery are required to reduce the sound levels produced by heavy machinery. Another approach is to contain the sound levels from the heavy machinery. Reduction of sound levels can be achieved by sound insulation or absorption.
What is the difference between sound insulation and sound absorption? The Merriam-Webster dictionary defines insulation as “a material or substance that is used to stop heat, electricity, or sound from going into or out of something” and sound absorption as “interception of radiant energy or sound waves”. The main differences between sound insulation and sound absorption lay in their goals and type of materials and are outlined below.
Soundproofing a compartment has different goals. One goal is to prevent external noise from entering the room. Another goal is containing and absorbing sound or noise within the room so that the sound level is reduced. Insulation material acts as a barrier in preventing sound from moving from one room to another. Noise absorbing material within a room absorbs the sound waves and reduces its effects. To summarize:
- Sound levels are reduced by using insulating materials as barriers, i.e. Sound insulation;
- Soundwaves are absorbed by sound absorbing materials to reduce sound levels, i.e. Sound absorption.
Although sound insulation and absorption offer different solutions, generally they are applied in combination to reduce noise, which works more effectively.
Insulation materials should be able to reflect and block the transmission of sound waves. Therefore, the material is required to be heavy and dense without pores or cracks, such as a gypsum board. Absorbing materials are generally porous, loose and breathable so that sound waves can pass through and be muted. Materials like stone wool or alkaline earth insulation are perfect sound absorbers.
As mentioned before, it is common that sound insulation and sound absorption are applied in combination on architectural outfitting. The sound absorbing material can absorb and reduce the sound within a room which generally provides sufficient protection against noise. When this proves to be not enough, sound insulation can be applied by means of a gypsum board, which blocks external sound waves of entering a compartment.
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