Historic Acoustic Materials

Products using these materials:

   AcoustiPack™ Deluxe
   AcoustiPack™ Standard
   AcoustiPack™ SFF
   AcoustiPack™ Antec Sonata I/II
   AcoustiPack™ Antec Sonata I
   AcoustiPack™ C6607
   AcoustiCase™ C6607
   AcoustiPack™ Antec 3700 BQE

Acousti Products use only highest quality professional studio-grade materials. They are formulated for acoustic effectiveness within the sound frequency range of 100Hz - 10KHz (which are those commonly associated with vibration and noise from hardware components). More details on sound performance.

Our acoustic materials have been copied by other companies since we originally formulated them, so beware of cheaper alternatives! - especially materials that can contribute to internal dust (called shedding), and also disintegrate easily if scratched when fitting them.

Our products are certified to international flammability standards, and importantly, this includes the adhesives. It is the performance and quality of our materials that places our products at the higher-end of the market.

The majority of our acoustic material products are made from a uniquely designed dual-layer composite material. This is comprised of acoustic foam, composite adhesives and a dense acoustic barrier mass layer. Information regarding these component materials is below. More details on component materials

Acoustic Composite Sound Absorption Properties

The composite material has been specifically designed to have a low-reflection upper surface, and high-absorption lower mass to absorb remaining sound energy. Sound energy is captured and adsorbed, to a degree, within the upper acoustic foam layer. Remaining sound energy reaching the very dense mass layer at the base of the composite is then converted to thermal energy at a molecular level. As this process occurs at a very small scale, and involves very low levels of kinetic energy, so does not result in a noticeable increase in the temperature of the composite.

Acoustic Composite Ignitability

Our Acoustic Composite material has been tested to British Standard BS 476 Part 12 (1991) 'Method of test for ignitability of products by direct flame impingement'. The following products have passed the Ignition Source A for 120 seconds - designed to represent a possible end-use ignition hazard (i.e. first flame after electrical failure) with the application of a flame at 45° for both surface burn and edge ignition:

• PASS - 4mm Acoustic Composite (1mm barrier, 3mm foam as used in AP SFF)
• PASS - 7mm Acoustic Composite (2mm barrier, 5mm foam as used in APS & APD)
• PASS - 17mm Acoustic Composite with AcoustiContour™ (2mm barrier, 15mm foam, as used in APD)

BS 476-12:1991 is an appropriate fire test for acoustic materials for application inside PC and Server Enclosures. The test stipulates that 'where materials will be fixed to substrates in practice, analogous procedures shall be used to prepare test specimens'. During the above flammability testing, soundproofing material samples were adhered to a solid 1mm steel plate and ignitability tested as if in situ, rather than in free air (which does not occur in practice). For more details see the BSI Website.

Acoustic Materials Sound Performance

Image showing the graphical results of two sound tests; one for the acoustic foam and another for the acoustic barrier mass. Both materials are used in Acousti Products. The acoustic foam (thickness 25mm) was tested using the test standard ASTM C384.

The results (shown as a black curve with scale on the left hand axis) show that the sound absorption sharply increases from approx 0.2 to approx 0.9 from 200Hz to 1000Hz, and then remains high, above 0.9 from 1KHz through to 7KHz. The acoustic barrier mass was tested using the test standard ISO R140. The results are displayed as Sound Transmission Loss (STL) in dB as a grey line (using the log scale on the right hand side of the graph). The STL remains high above 10dB throughout the frequencies tested from 100Hz to 4KHz. There is a marked increase in effective noise absorption from 200Hz to 500Hz, and from this point the STL remains above 20dB.

The test results show that the acoustic barrier mass has a relatively high sound absorption efficiency at the lower test frequencies and the acoustic foam 'optimal' sound absorption occurs above 1KHz.

Component: Acoustic Foam

The acoustic foam we employ is a charcoal grey professional semi-open cell studio-grade dense acoustic foam that is non-shedding and does not crumble or generate dust. This is approx. 60-65Kg/m³ - which is unusually dense compared to cheaper alternative noise-reduction foams. The reasons for selecting such a high-density foam are:

• higher density improves the sound absorption efficiency at lower frequencies (sub-1KHz) - which is critically within the range we are seeking to eliminate
• higher density materials help to maintain a low flammability performance, and
• higher density foams can withstand being manufactured into thin 'low-reflection' layers for dual-layer composites

The acoustic foam is certified to the highest appropriate UL94 specification for a foamed product (UL94 HF1), and also ISO 3582, FMVSS 302 and DIN 4102 for low flammability, and can be operated normally within the temperature range -40°C to +100°C.

Component: Acoustic Barrier Mass

The dark grey/black flexible acoustic barrier mass is manufactured from an EVA-based polymer compound incorporating additional components to increase the product's mechanical strength, density, durability and fire resistance. Our uniquely developed acoustic barrier material is a non-PVC based compound that is bitumen free and therefore does not give off undesirable odours or vapours when warm. It is very dense at approx. 2,500Kg/m³, and does not contain unrefined aromatic oils, lead, chromium, cadmium, or mercury. It is designed to add mass to computer casing; for example, sheet aluminium, steel, alloys and non-glossy plastic surfaces. The mass of the material acts to absorb sound energy at a molecular level as an acoustic absorption barrier, significantly reducing noise transmission and also reducing any natural resonant frequencies of the substrate to which it is adhered.

The acoustic barrier mass is certified to international standards for extremely low flammability. We believe it is the most low flammable acoustic material for our application available on the market. Standards include FMVSS302 and ISO 3795 (Burn Rate B, <5mm/min). It can be operated normally within the temperature range -25°C to +80°C.

Component: Adhesives

Acousti Products use non-flammable adhesives throughout our products. Our high temperature self-adhesive is less odorous than solvent-based adhesives in some alternative products. The adhesives we employ can be operated normally within the temperature range -20°C to +100°C. If the materials are applied lightly at first, and a mistake is made during positioning, our self-adhesive allows for the materials to be peeled off and then reapplied. The adhesives are 'set' by applying pressure and become more fast with time. Do not remove the materials once they have been firmly applied, as this will damage the self-adhesive.

top