The two most commonly used sound absorption materials are specialized acoustic fiberglass and high-quality acoustic foam. Although acoustic foam may look and feel similar to other foam products, there are dramatic differences in cell structure and density. Foam is made of millions of tiny cells, and the size of the cells will greatly impact the acoustic performance of the material.
Physical Properties - A foam’s physical makeup is measured in Pores Per Inch, (PPI). Porous foam found in cushions has a rating of 25 or 30 pores per inch, while quality acoustic foams have a PPI of 80. The more cells, the more acoustically absorbent the product. The firmness of the foam will also impact its performance.
Firmness - Firmness is measured in Indentation Load Deflection, (ILD). Foam with a higher ILD will absorb more low frequency sound, and foam with a lower ILD will absorb more high frequency sound. Quality acoustic foam is formulated to a firmness that balances the two. The shape and thickness of the panel is also important in determining the amount and frequency range of the sound being absorbed. Using foam not specifically manufactured for acoustic treatment can be too reflective or have frequency voids.
Durability - Since acoustic foam panels are in close proximity to people, they must be durable and be able to withstand being brushed up against without crumbling and wearing away. Egg crate foam used in packaging is a good example; although it may look similar in appearance to acoustic foam, it is easily picked apart and will become brittle with age. A good acoustic foam panel will stand up to accidental abuse much longer than conventional products.
Fire Retardancy - The single most important characteristic difference between acoustic and conventional foam is its fire retardancy. Acoustic panels can be exposed to heat or open flames as well as wiring and electronics, posing a potential fire hazard. The standard test for determining a material’s fire retardancy is ASTM-E84. Always check the manufacturer’s specifications to insure that their product has been tested in a certified testing lab and has passed this test.
Aesthetics - Appearance may or not be an issue for your particular application, but it certainly is another factor that differentiates acoustic foam from conventional foam. Manufacturers of cushion and mattress type foams aren’t concerned with blemishes and imperfections since the material is always covered. If you are treating a professional sound studio, aesthetics will be important.
SONEX acoustic foam panels are manufactured by Pinta Acoustic and are made from an open-celled fiber free structure of willtec foam giving them an extremely low density, making them lightweight and flexible. Willtec foam is made from porous melamine and meets all ASTM E-84 requirements for flame spread and smoke density, as well as the new UL 1715 room fire exposure test. The open cell willtec foam enhances the material’s ability to dampen sound over a wide range of frequencies. Willtec foam is easy to cut, mold, and trim, and is installed with a water based adhesive for quick and easy installation. SONEX acoustic wall and ceiling panels are available in a wide variety of styles, colors, and thicknesses to provide aesthetics as well as performance.
Studiofoam acoustic foam by Auralex Corporation has become a world standard and utilizes a proprietary formulation that has the cell structure, density, cuts, and chemistry that yields a professional acoustical product offering excellent absorption with high durability. While low quality foam panels can simply crumple to dust over time due to environmental conditions such as exposure to lighting, humidity, smoke, temperature, Auralex Studiofoam will not degrade or decrease in performance. Auralex Studiofoam panels are precision cut and held to tight tolerances to insure the panels match up from piece to piece when installed, and is colored through and through as part of a proprietary chemistry and production process. Other manufactures simply surface paint their panels which reduce performance and allow the edges to show a different color than the surface for a less than professional finish. Auralex acoustical foam is specifically designed to be fire retardant tobetter meet building and fire codes. Auralex fire retardants are chemically added to the foam not sprayed on.Auralex Studiofoam panels are available in wide variety of styles, colors, and thicknesses for any application.