Whether it’s due to living next to a road or in a condominium with poorly constructed walls where you can clearly hear your neighbors, we have to endure these noise disturbances for a long time. Wouldn’t it be great if we could eliminate these disturbances?

At night, you wouldn’t hear street noise or neighbors arguing, and during storms, you wouldn’t be startled awake by thunder. It may sound like a dream, but it’s actually achievable.

TL (Sound Transmission Loss) is the reduction in sound energy when passing through materials at different frequencies. TL values show how many decibels of sound a material can block at each frequency range.

STC (Sound Transmission Class) is the sound insulation rating of materials, derived from the average TL values. Higher STC values indicate better sound insulation. STC values cannot be added together. STC is determined through material testing, for example:

• 9mm gypsum wall with 50mm sound insulation has an STC of 35
• 10cm solid brick wall has an STC of 43
• 9mm sound-proof ceiling with 50mm sound insulation has an STC of 30

SAC (Sound Absorption Coefficient) is the sound absorption value of insulation at a specific frequency. SAC = 0.8 at 500 Hz means that at 500 Hz, this material absorbs 80% of sound and reflects 20%.

NRC (Noise Reduction Coefficient) is the average sound absorption value of materials. For example, NRC = 0.8 means the material absorbs approximately 80% of sound overall and reflects 20%. NRC = 1 means sound enters and doesn’t exit at all, effectively absorbing 100% of sound.

Sound absorption and sound insulation have similar names but different applications.

Sound Absorption is insulation material that absorbs sound to reduce echo and reflection. Its effectiveness is measured by SAC and NRC values – higher values indicate better sound absorption. It’s suitable for smooth-walled rooms without furniture, churches, meeting rooms, studios, and other spaces to reduce echo and sound reflection.

Sound Insulation is material that prevents sound transmission and reduces sound passage. Most are open-cell structure fiber insulations that must be used with wall panels or other wall structures. Their effectiveness is measured by TL and STC values – higher values indicate better insulation. Suitable for bedrooms, pubs, residential homes, office buildings, meeting rooms, and other spaces with noise issues.

Comparison Table of Sound Insulation and Sound Absorption

The principle of sound insulation is preventing sound transmission to the other side of the wall. Effective sound-blocking walls are typically heavy, such as clay brick, lightweight brick, or cement board, and must have sound-absorbing material inside to absorb sound energy for noise reduction.

Let’s compare Smart Board walls with and without sound insulation.

Sound insulation installed in wall cavities or placed on ceilings should be open-cell structure type. When sound energy reaches the insulation, it absorbs and disperses the energy, reducing sound volume. Sound insulation comes in various brands and materials. We recommend quality brands with certified standards.

ROCKWOOL Safe ‘n’ Silent Pro sound insulation is stone wool insulation with non-combustible properties, high melting point, excellent heat protection, and high sound absorption. The lowest grade has an NRC = 0.90, making Safe ‘n’ Silent Pro the most popular choice for soundproof walls.

• Order products: https://3t-insulation.com/rockwool-safe-n-silent-pro/
• Product catalog: ROCKWOOL Safe ‘n’ Silent Pro Sound Insulation Catalog

SCG Cylence Zoundblock sound insulation is glass wool insulation made from recycled glass with high thermal resistance and sound absorption. Covered with black moisture barrier, it’s dust-free during installation and easy to install. Available in 50mm and 100mm thickness.

• Order products: https://3t-insulation.com/cylence-zoundblock/
• Product catalog: SCG Cylence ZoundBlock Sound Insulation Catalog

MicroFiber MicroTone NoizeStop sound insulation is glass wool made from recycled glass with high sound absorption. The yellow insulation is covered with clear moisture barrier or aluminum foil to prevent fiber shedding. Available in 50mm and 100mm thickness.

Product catalog: MicroFiber MicroTone Noizestop Sound Insulation Catalog