Schalldämmung durch Gummi- und Stahlfedern

In an investigation on the sound insulation of rubber and steel springs in the frequency range 20 to 2000 c/s good agreement between theory and practice was found. The larger internal damping of rubber springs — the loss factor being about ten times that of steel springs — produces good insulation over the whole frequency range. Beside simple mass + spring systems, mechanical filters were tried, i. e., systems of two or more springs separated by masses. Filters are better than simple systems above a critical frequency but have disadvantages at low frequencies.