The term “soundproofing” is often used informally to mean either “sound isolation” or “sound absorption”. These two meanings are quite different, and achieving sound isolation requires different treatments or room modification that achieving sound absorption.
Sound waves typically projects from their source in all directions. While some sound travels directly to the destination of interest (e.g. a microphone, another individual, etc.), most of the sound bounces in all directions between surfaces within the room. Some sound may escape through gaps or openings in the room surfaces, and some may be transmitted through/by the structures of the rooms walls, floor, or ceiling.
After some delay due to additional travel distance along this path of many reflections, those reflected sounds may reach the destination of interest. The resulting effect is many copies of the sound arriving at slightly different times, and we call this “reverb”. With each reflection, some frequencies will be absorbed and scattered differently than others, giving each room a different tone to its reverb characteristics.
Sound absorption, or sound treatment, is used to reduce the amount and duration of reflected sound within the space. It does this by absorbing sound when it strikes acoustic panels or other acoustical treatments, reducing the amount of sound that is left bouncing around the room. This also has the effect of reducing the loudness of sound in the room, especially sounds sourced far away from the position of the listener.
The purpose of sound absorption acoustical treatments is to improve the listening experience inside the room. Acoustic panels are a type of sound treatment that is used to absorb sound into its layer of porous acoustical material. As sound waves pass through the acoustic panel, they lose energy through friction between the air particles and the material its passing through. It’s important to note that if sound can pass into a material, it can also pass through a material, if it is not completely absorbed within that material.
Acoustic panels are designed to absorb a high percentage of the sound that strikes them, not to block that sound with a solid surface that reflects the sound back into the room. Add acoustic panels to a room, and you’ll increase sound absorption, reduce reverb, and quiet the room down.
Sound isolation is reducing the amount of sound that passes in and out of the space by making it more difficult for sound waves to travel through the structures of the walls, floor, and ceiling. This is about keeping sound from leaking through where you don’t want it to be. This process requires closing/sealing gaps and openings where sound can travel, and construction-project-type changes such as adding a second layer of drywall (with a rubber absorption sealant in between), floating floors on rubber isolation blocks, or designing dead air spaces between walls.
Your choice between sound absorption treatments and sound isolation treatments depends on what problem you are trying to solve. Too much reflected sound inside the room, or too much sound leaking into/out of the room? Now that you know the difference between the two terms, you can make an informed decision that will best work for your space. ATS Acoustics offers many different sound absorption options such as acoustic panels,bass traps, diffusers, and much more. We also sell some products used in sound isolation projects.