Appropriate Specifications of PET Acoustic Pads for Enhancing Sound Absorption

With the recent growth of eco-friendly interior design and office acoustic improvement markets,PET Acoustic Panels have become one of the most prominent nonwoven products.

However, not all panels made from PET material exhibit high sound absorption performance.

In this post, we will explore which specifications of PET acoustic pads deliver the best sound absorption efficiency.

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Density

The density of PET acoustic pads is a critical factor that determines both sound absorption performance and structural strength.

If the density is too low, the panel absorbs only high frequencies while allowing low frequencies to pass through. Conversely, if the density is too high, the internal pores decrease, causing sound reflection and reducing absorption efficiency.

In general, PET fiber structures with a density of 180–230 kg/m³ demonstrate stable sound absorption characteristics even in the mid-to-low frequency range (250–1000 Hz).

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Thickness

The Noise Reduction Coefficient (NRC) is an index that quantifies sound absorption efficiency on a scale from 0 to 1. Materials with an NRC of 0.75 or higher are classified as high-performance acoustic absorbers, typically used in commercial spaces, offices, and studios.

PET acoustic panels, produced through needle-punching and thermal pressing, can achieve high NRC values even at lower densities compared to perforated panels (e.g., MDF-based types).

So, at what thickness do PET acoustic pads maintain a high NRC?

According to standard testing methods (ISO 354 / ASTM C423), panels with a thickness of 9 mm to 24 mm typically exhibit NRC values in the 0.75–0.95 range, providing balanced absorption across high to mid-low frequencies.

Sound absorption performance is highly sensitive to thickness variations.When the panel is thinner, the air cavity decreases, shifting absorption toward higher frequencies. Conversely, thicker panels enhance mid-low frequency absorption but increase both weight and cost.

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Heat Resistance

Heat resistance is another critical factor in evaluating PET acoustic pads.

Since PET panels are often used in environments exposed to heat—such as lighting systems, HVAC ducts, and automotive interiors—they must maintain dimensional stability under varying temperature conditions.

By ensuring thermal stability above 120 °C, PET acoustic pads can be used long-term without deformation or shrinkage.

This performance is verified through heat deformation tests (e.g., ISO 1798). Panels that meet this standard remain stable in shape even under high-temperature conditions.

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In conclusion, PET acoustic pads achieve the highest sound absorption performance under the following specifications.

Quality Element	Standard	Reason for Specification
Density	180–230 kg/m³	Balance between absorption and strength
Sound Absorption (NRC)	0.75–0.95	Ensures high acoustic performance
Thickness Tolerance	±0.5 mm	Dimensional stability and quality consistency
Heat Resistance	≥ 120 °C	Maintains durability without deformation

DK FIBER supplies PET fibers used in the production of acoustic materials and can provide customized fiber colors according to customer requirements.