Acoustical material for use in association with noise generating machinery

摘要: An improved acoustical material, which is simple in construction and uses conventional, inexpensive materials, for use as a lining material association with noise generating machinery, comprising, combination, composite layer of plural layers porous will not deteriorate, swell or retain oil, solvents, water such are found has flow resistance between 20 rayls 80 rayls, highly acts dead air space relative to the composite.