The sound insulation of doors, or moving room closures in general, depends essentially on the tightness within the area of the hinges. For this reason test certificates concerning the sound insulation of a door leaf are only as good as the testing of a car at a standstill - they do not say anything about the suitability in the fitted state during actual use. Besides a corresponding weight per unit area Contrast Akustik noise control gates therefore provide a rebate seal fitting perfectly close all round which also prevents the passage of sound in the threshold area.

Handling of the doors supplied by us is extremely practicable as a result of the precision manufacture and high stability. By a single pressure closure which, depending on the size of the door, moves one or more worms and rolling gudgeons, the closing device can be actuated without excessive exertion. The weighted sound-insulation index for the Contrast Akustik noise control gates amounts to 50 dB. In the case of a version as a sound interlock / sluice, two doors one after the other, values greater than 60 dB can be achieved. The above-mentioned special versions can reduce the weighted sound insulation index.