第三讲作业_19904247（Lecture 3 _19904247）.docVIP

第三讲作业Lecture 3 Lecture three A swimming pool, in the design of sound absorption, should use _________ materials. (hint: not only to absorb sound, but also to consider waterproof.) A, glass cotton B, plywood resonance sound absorption structure C, perforated plasterboard D, perforated aluminum alloy plate E and slit acoustic absorption brick Two, the following instructions are correct: A, the same bulk density of glass wool, the greater the thickness, the greater the sound absorption effect, and is proportional to the relationship. The greater the power of B and sound source, the greater the sound absorption coefficient of the obtained material. C and sound sources in different positions, the sound absorption of materials will be slightly different. D, perforated gypsum board ceiling with 12mm thickness and 9mm thickness of the same perforation rate, the sound absorption performance is exactly the same. Three, in order not to affect the sound absorption properties of porous materials, can be used _______ perforation rate of perforated plate do cover.. A, 5% B, 10% C, 20% D, 32% Four, the following instructions are correct: A, in general, the theater reverberation time than the full long reverberation time. B, the glass wool in the ceiling of the room perforated gypsum board is damp and the room reverberation time will be shortened after moisture absorption. C, a hall of low-frequency reverberation time is too long, empty laying wood floors and wood paneling will improve after. D and the back wall of the theatre often see holes in it for the purpose of beauty. Five, how about the noise in narration, ________ is wrong. A, in order to reduce indoor noise, and in the wall and ceiling on the set of perforated gypsum board, if the board does not have rock wool or glass cotton, almost can not play any role. B, interior layout four, each produces 70dB equipment, indoor noise level of about 76dB. The upper wind direction should be arranged in the C and th