ROLFON – how it works
Generally used acoustic absorbents inlcude foams, mineral wools, fleeces, acoustic ceilings and plasters or textile materials. Their structure is porous or fibrous, they contain numerous air cells and the absorbing mechanism employs flow resistance. Such absorbents reduce high and medium frequencies well, but they are of no use against lower frequencies.
To successfully absorb low frequencies we need specially shaped acoustic structures, called "resonators", which employ mechanical resonance.
ROLFON™ hybrid is a unique construction made of two crucial elements: mineral wool sound absorber and a set of special quater-wave resonators. They are combined in the way that both the surface of the absorbent and the apertures are exposed to acoustic waves. This way the wave is absorbed by two mechanisms: the resonant mechanism (characteristic for acoustical structures) and the flow resistance mechanism (characteristic for sound absorbents).
In result, we achieved a broader spectrum of effective absorption or greater absorption in selected subfrequencies, as the absorbing features of both parts are combined.
ROLFON™ hybrid is a roller made of profiled mineral wool, 15 cm (5.9 in) in diameter and 1 m (3.28 ft) long, with 4 specially shaped acoustic resonators inside.
ROLFON™ roll is a true "isolator", which eliminates reverberation noise in two ways, withouth the thickness of absorbing material.