A hydraulic power pack, which was not especially noisy for its own operator, was transferring vibration at audible frequencies to a steel floor under which operators had to work from time to time. The steel floor effectively became a loudspeaker, creating noise levels of 88dB.
The power pack was mounted on properly specified antivibration mounts, the selection of which related to its overall weight and the frequencies that needed to be controlled.
Noise was reduced to such an extent that it could not be measured in the climate of the background factory noise.
This solution should work in a wide variety of applications where the source of airborne noise is a relatively large flat surface connected to a vibrating mechanism. Great care should be taken, however, when selecting AV mounts as the wrong choice can amplify noise and even damage equipment.
The noise levels were reduced by 4dB to 84dB.
The price of the anti-vibration mounts was £220.
Marley Eternit Ltd. & PDA Ltd.