SOUND-MEASURING ECHO-FREE ACOUSTIC CHAMBER ( VARIANTS ) Russian patent published in 2003 - IPC

FIELD: acoustic measurements, sound wave analysis, sound-absorbing structures. SUBSTANCE: in correspondence with first variant there is proposed sound-measuring echo-free acoustic chamber that includes space limited by wall surfaces, measuring microphone and sound absorber comprising layer of glass wool, electromagnetic screen and layer of sound-absorbing wedges separated by air gap. Layer of glass wool has thickness 150.0- 900.0 mm and is pressed against walls with the aid of steel sheet or metal grid with mesh spacing between 0.05-0.5 mm, air gap has thickness of 10.0- 15.0 mm. In accordance with second variant layer of glass wool is pressed against walls by means of resonance sound absorber produced from thick cloth. Electromagnetic screen can come in the form of two layers made of metal sheet and metal grid parallel to sheet or in the form of two parallel layers made of metal grid which divide thickness of layer of glass wool in 1:2 ratio. Resonance sound absorber can include two parallel layers of thick cloth placed at some distance from wall that does not exceed thickness of layer of glass wool and which divides thickness of layer of glass wool in 1:2 ratio. EFFECT: raised absorption factor. 8 cl, 3 dwg, 1 tbl