Cross point is a soft, attractive, sound-absorbing wall fabric. The fabric is made of solution dyed polypropylene fiber for its inherent stain resistance, durability, and easy maintenance. Cross Point is available in a wide variety of colors and is easily applied with a heavy duty wall covering adhesive leaving a seamless finish. The construction will not ravel or snag and is Velcro compatible.

The Speaker Cloth line is designed and engineered for sound transmissibility and aesthetic appearance. Specially engineered fabric construction allows the sound to pass through the synthetic round threads with minimum interference. The result is a top quality Speaker Cloth engineered for sound reproduction suitable for walls, organ lofts in churches, for covering clusters of speakers in auditoriums, sound studios and other interiors. Speaker Cloth is flame retardant Class 1 fire-rated. 

http://www.noisecontrolproducts.com/sound_proofing_fabrics.htm