5 shows the values of the longitudinal sound wave attenuation coefficient after analysing acoustic properties of wood chipboard and gypsum cardboard.
8, used in the experiment, shows that in the case of a medium high sound, the structure composed of dovetail glass plastic board, rockwool (100 mm) and wood chipboard (2 x 10 mm) has better acoustic properties.
The highest [DL.sub.R] index values (32-33 dB) were recorded when using a wood chipboard, 100 mm thick, as a component of the structure (structures No.
When studying the airborne attenuation index of individual materials, the best values were obtained using a wood chipboard.
The highest [mu] coefficient values (620-710 [m.sup.-1]) were recorded in the sample of wood chipboard.
Out of the investigation materials, the best structure, according to the airborne sound attenuation index and the sound insulation index, was obtained upon composing a noise-reduction wall of a wood chipboard frame filled with fibreglass or rockwool ([DL.sub.R] = 33[+ or -]1 dB).
Medium- and high-frequency sounds are most efficiently reduced by a structure composed of wood chipboard with fibreglass or rockwool filling.
4, the second zone), the most efficient materials determined in terms of noise reduction are gypsum cardboards and wood chipboards. When using these materials in a medium high-frequency range, the sound reduction of up to 35 dB was recorded.