of conventional wall or floor ceiling assembly materials are not currently being used in sound control applications an example of such a material that is also non resiliently compressible is isocyanurate foam sheathing also called u201c iso foam u201d which is currently used only for thermally insulating exterior walls and not for sound deadening interior wall or floor ceiling assemblies another example is blue closed cell sill seal foam a non resiliently compressional material also not normally used for sound deadening interior wall or floor ceiling assemblies of course any material with young 39 s modulus less than the young 39 s modulus values of conventional wall or floor ceiling assembly materials may be used in the present invention as sound deadening side 109 as described above however a preferred range of sound control performance results when the material has a young 39 s modulus from 50 to 600 psi sound deadening side 109 preferably has a thickness of between about 0 125 to 1 inch and may be manufactured from a wide variety of materials including but not limited to a cellulosic fiber material e g recycled newsprint perlite fiber glass epdm rubber or latex side 109 also is preferably manufactured to a density of 9 to 14 pounds per cubic foot which is less than the density of current sound control boards for example 440 sound a sote u2122 has a density of 26 to 28 pounds per.