What Material Absorbs Sound the Best?

What Is the Best Material for Acoustic Panels? NRC Data

Rigid fiberglass and mineral wool board absorb sound best per inch: 2 in. of Owens Corning 703 rates NRC 1.00 and 2 in. of Rockwool Comfortboard 80 rates 0.95, compared with 0.75 for 2 in. acoustic foam. So the best material for acoustic panels is fiberglass or mineral wool board, 2 in. thick for echo and 4 in. or more where bass is the problem.

Bar chart of maker NRC: Owens Corning 703 fiberglass 0.70 at 1 inch, 1.00 at 2, 1.15 at 3 and 4; Rockwool Comfortboard 80 0.75 at 1 inch, 0.95 at 2, 1.00 at 3; Auralex Studiofoam Wedge 0.50 at 1 inch, 0.75 at 2, 0.90 at 3, 1.10 at 4 — NRC comes from the Owens Corning 703 (opens in a new tab), Rockwool Comfortboard 80 (opens in a new tab) and Auralex (opens in a new tab) data sheets. Foam needs 4 in. to beat what fiberglass does at 2.

The catch is bass. NRC averages absorption at 250, 500, 1,000 and 2,000 Hz (Acoustical Society of America (opens in a new tab)), so it skips the low end, and down there thickness wins: 703 absorbs 0.15 at 125 Hz at 2 in. and 0.56 at 4 in. If you're buying for a studio or home theater, check the 125 Hz column on the data sheet first.

If fire's a concern, go with stone wool: Comfortboard 80 is noncombustible to ASTM E136 with a flame spread index of 0. What acoustic panels are made of walks through each core, and fiberglass and mineral wool soundproof panels compares the boards by density and fire rating. None of these blocks noise through a wall. The soundproof panels guide shows what does, and there are more answers in the soundproof panels FAQ.

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