Types of surround material have certain benefits and drawbacks.Foam
This is a material with polyester fibers blended in for extra strength and durability.

Cloth or Textile
This is the name for a variety of cloth fabrics used for speaker construction. Used to replicate the sound of silk tweeters.

Rubber
Rubber offers excellent flexibility and durability.

Butyl Rubber
A rubber/butylene compound with excellent flexibility and durability.

Santroprene
This is a popular new durable plastic material used in many different products apart from speakers.

Urethane
Urethane is a plastic compound with proven flexibility and weather resistance and is an advance on natural rubber.