Acousta-Stuf Polyfill Speaker Cabinet Sound Damping Material 1 lb. Bag Acousta-Stuf is a synthetic material made from crimped fibers. It is an excellent choice for filling or stuffing small enclosures or transmission line cabinets. Long fiber wool has been a favorite among serious speaker builders but Acousta-stuf is less expensive than long fiber wool and does not have the problem of harboring moths. Acousta-Stuf will also outperform Dacron, foam, and fiberglass. Acousta-Stuf is a sound absorption, dampening fiber that will deepen bass, provide cleaner midrange and improve the dynamic extension of any speaker system. There are no health hazards with Acousta-Stuf and no mask or gloves are needed when using this product; the melting point is a very high 490°F. Most sealed and vented enclosures require 1/2 lb. of dampening material per cubic foot of enclosure. For best results it is recommended to loosely fill the material throughout the enclosure.