What Are Acoustic Panels Made Of?
Updated
Acoustic panels are made of a porous core, usually fiberglass, mineral wool, open-cell foam or pressed polyester (PET) felt, wrapped in fabric or faced with wood slats. The core does the absorbing, so it decides how well the panel works: at 2 in., fiberglass board rates NRC 1.00 and acoustic foam 0.75.
| Core | Thickness | NRC | Source |
|---|---|---|---|
| Fiberglass board | 2 in. | 1.00 | Owens Corning 703 (opens in a new tab) |
| Mineral wool board | 2 in. | 0.95 | Rockwool Comfortboard 80 (opens in a new tab) |
| Open-cell foam | 2 in. | 0.75 | Auralex Studiofoam Wedge (opens in a new tab) |
| PET felt | 12 mm | 0.45 | Acoufelt (opens in a new tab) |
Fiberglass and mineral wool boards are the ones that get wrapped in fabric, and that fabric is picked to let sound pass through to the core. Fiberglass and mineral wool soundproof panels compares the boards by density and fire rating. Foam and felt often go up bare. On a slat panel, it's the felt behind the slats that does the absorbing.
Watch out: "Soundproof panels" made of foam or felt are absorbers, not blockers. Panels that actually block noise are made of heavy or layered materials, like mass loaded vinyl at STC 26 for 1 lb/sq ft (Johns Manville (opens in a new tab)). A 2 in. fiberglass panel weighs half that.
If your problem is noise through the walls, the best material to block sound covers what to buy. The soundproof panels guide compares every panel type, and there are more answers in the soundproof panels FAQ.