Concrete masonry walls have long been valued as a primary material for soundwall construction for their aesthetics, durability, and noise reducing attributes as stated by Sound Transmission Class (STC) values. STC is a one number rating from the 16 values of Sound Transmission Loss (STL) data obtained by application of the appropriate American Society for Testing and Materials (ASTM)standards.

Since Proto II™ is constructed of standard concrete masonry units, key attributes of cmu walls translate to Proto II™ - including STC values. Therefore, Proto II™ walls meet the same specifications for soundwalls as conventional cmu walls.

Typical STC values for ungrouted cmu walls:

4-inch Wide - 40 to 48
6-inch Wide - 44 to 48
8-inch Wide - 45 to 52