Abstract: The invention relates to a lightweight substance molded body made of a lightweight aggregate and a sintering auxiliary agent, wherein said molded body consist of a sintering product containing 60-95 wt. % lightweight aggregate with 40-5 wt. % water-soluble alkali silicate.

Abstract: Structured pre-form bodies as panel lining for wide-band sound absorption are made of an open-cell foam material having a rigid framework co-vibrating in a resonant manner at low frequencies. The pre-form bodies have a base layer and a columnar structure positioned directly in front of or on the base layer. The columnar structure has a non-symmetrical distribution of height and cross-section, thereby forming a wide-band tuned moderator gap and the columnar height corresponds approximately to the density of the base layer. The columnar structure has a framework resonance adjustable as a function of parameters of the base layer.

Abstract: The invention relates to a lightweight substance molded body made of a lightweight aggregate and a sintering auxiliary agent, wherein said molded body consist of a sintering product containing 60-95 wt. % lightweight aggregate with 40-5 wt. % water-soluble alkali silicate.

Abstract: A low reverberating room for the entire auditory range. In particular, for ow frequency ranges below 100 Hz, in which the walls and ceiling are covered with sound absorbers. The sound absorbers on a surface of about 70-90% of a room, not including the floor, have a depth of <0.5 m preferably <0.3. The sound absorber also has a closed, plane but acoustically permeable surface, are built up of multiple layers. The sound absorbers are about 20-70% in similarity to composite-plate resonators. They are also provided with inside plates, made of metal or heavy foil, which are designed of varying thickness for absorption in various frequency ranges.