Sound Insulation
Noise reduction is achieved in three ways with cellulose. The first is that cellulose completely fills cavities leaving few air pockets for sound to travel in. The second is the cellulose material's ability to trap air. The significant difference between noise reduction with cellulose and fiberglass is its density.
Cellulose is approximately three times denser then fiberglass. This helps deaden the sound through walls and between floor levels.