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8 Posts in this encyclopedia categoryNatural frequency/Resonant frequency
Natural frequency is the frequency at which a vibratory system oscillates after it has been excited. Excitation of a system/object by a sound source that matches its natural frequency leads to resonance.
Noise barrier
A noise barrier is a wall that prevents the propagation of noise, or shields an area from noise. Noise barriers are often erected along railway or motorway sections.
Noise control
Equipping the room with noise control materials reduces the sound level (and hence the perceived noisiness) and improves speech intelligibility. Such an improvement of acoustic conditions makes for a much more pleasant atmosphere. Porous and fibrous materials such as open-cell foams or non-wovens are excellent sound absorbers. But also closed-cell foams with a special cell structure, for instance our soni RESIST, score with good sound absorption capacity.
Noise control
Noise control includes the full range of measures that help reduce and/or contain noise or even prevent its generation in the first place. Noise control is aimed at preventing health damage caused by exposure to noise.Noise control encompasses all measures that help reduce the transmission of sound between a sound source and a target zone or recipient.
NRC (Noise Reduction Coefficient)
The NRC of an acoustical material is its average absorption coefficients in the frequency range from 250 to 2,000 Hz. Hence the NCR reflects the sound-absorbing characteristics of a given material.