A recently-completed cinema building is exposed to airborne noise and groundborne vibration from trains that pass within five meters from the exterior facade. During construction, the building was treated with several noise control systems to help mitigate potential disturbance from the passing trains. One of these systems is a concrete raft (or "floating") floor supported by glass fiber pads. The raft floor is very helpful for controlling the effects of groundborne vibration above 100 hertz.

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... ce the building was completed, it was found that the noise reduction was excellent in the speech range (i.e., at frequencies greater than 200 hertz, train passby events were not measurable within the cinema). For frequencies below 200 hertz, however, the interior noise level increased 10-to-15 decibels as the trains passed outside. In this lower frequency range, the noise reduction varied significantly throughout each train passby event. The variation in the "apparent" noise reduction is a result of groundborne vibration exciting the interior surfaces of the building.