Auralex MFI Mineral Fiber Insulation 2" 2x4 Foot Panel (Box of 6)The best way to tighten up a room's sound and make it more soundproof in the process is to design it right, build it tight and make the partitions as dense as possible. That's where this specialized Mineral Fiber sound insulation comes in. It's WAY more dense than the pink stuff and is specifically designed for acoustical usage. It yields much better bass trapping, overall absorption, thermal characteristics, moisture absorption and sound transmission