Hushboard sound-deadening board is normally used in conjunction with 1/2" or 5/8" gypsum board, such as ToughRock gypsum drywall; or DensArmor Plus paperless interior drywall. A conventional 2x4 stud wall using Hushboard and 1/2" gypsum board will achieve a Sound Transmission Class (STC) of 39. That will make loud speech in the next room audible as only a murmur. Premium-construction, sound-isolated walls with Hushboard can deliver STC ratings of 56. Loud speech in the next room would not be audible. Hushboard used with a conventional steel stud wall can help achieve high-quality sound isolation with an STC of 49. For acoustical test results using Hushboard panels, and more information about how to incorporate the panel in wall systems, download the Hushboard Sound Deadening Board Brochure (PDF: 364KB/4pgs) .