Volume 4, Number 1, March, 1996 - Noise News International

More documents

Recommendations

Info

THICK, POROUS LAYERSABSORB BOTH HIGH ANDLOW FREQUENCY SOUNDPorousmaterialthrough which air canpassoftenmakes a good sound absorber. Examples of suchmaterials include felt, foam rubber, plastic foam,textile fibers, and a number of sintered metalsand ceramic materials. If the pores are closed,the absorption is low. Thin porous absorbentshandle high tones. For good absorption below100Hz, the thickness required may becomeimpractical. Low frequency absorption isimproved with the aid of an air gap behind theabsorbing layer.Principle1.00.8absorption factor (indicates theportion of the incoming soundthat is absorbed_..0.60.40.2o10 5 2.5low tonesthickness of mineral wool1 cm mounted directly against the wall.- --. high tones44NoiselNews International1996 March
Application in large spacesExampleA workshop with intense low frequencynoise is provided with absorbers that areeffective for low tones. One part of the shopcontains space for hanging sound absorptivebaffles, which provide good low frequencyabosrption, and are easily installed. Atraverse leaves no room for baffles in theother part of the shop. Instead, horizontalsound absorptive panels are installed abovethe traverse, 20 em from the ceiling, toimprove the low-frequency absorption. Withsound absorptive material on the walls andceiling, the noise levels in the shop can bereduced 3 to 10 dB, except in the immediatevicinity of the noise sources.sound-absorptive bafflessound-absorptive panel onlowered frame1996 March NoiselNews International 45
Page 2 and 3: The Metady!!~TMAnechoic Wedge Syste
Page 4 and 5: • •I-Inee InternationalInstitut
Page 6 and 7: President's ColumnThe Need for Cons
Page 8 and 9: Editor's ViewIs Noise Part of the E
Page 10 and 11: FeatureProfessional Societies in th
Page 12 and 13: the United States of America (INCE/
Page 14 and 15: Arranged by the General Committee o
Page 16 and 17: acoustical environment and the prom
Page 18 and 19: elated to noise. These organization
Page 20 and 21: Table 1. Dates and locations of pas
Page 22 and 23: the Member Society meetings. These
Page 24 and 25: The INTER-NOISE 95 Proceedings are
Page 26 and 27: y distinguished acousticians from a
Page 28 and 29: companying persons may also wish to
Page 30 and 31: the prediction of road traffic nois
Page 32 and 33: • The role of mass-spring-mass re
Page 34 and 35: in hospitals in Saudi Arabia: a cas
Page 36 and 37: international airport, Malaysia. Di
Page 38 and 39: Inter-noise 96Name, organisation an
Page 40 and 41: THE INTER-NOISE SERIESThe INTER-NOI
Page 42 and 43: LARGE AND RAPID CHANGESIN PRESSURE
Page 44 and 45: SOUND SOURCES SHOULDNOT BE PLACED N
Page 48 and 49: PeopleGold Medal KamerlinghOnnes Aw
Page 50 and 51: Asia-Pacific NewsA. Lawrence, Asia-
Page 52 and 53: BooksThe Nature and Technology ofAc
Page 54 and 55: and Isolation Materials, Grommets a
Page 56 and 57: five special sessions on all aspect
Page 58 and 59: I•Do your work faster and moreacc
Page 60 and 61: BIOACOUSTICSANSI S3.7-1995, Coupler
Page 62 and 63: TAGSlFirst ISO/CD 3747-Acoustics-De
Page 64 and 65: International Advertising ContactsB
Page 66 and 67: DIRECTORY OF NOISE CONTROL SERVICES
Page 68: INTUITIVE AND POWERFULACOUSTIC SOLU

Volume 4, Number 1, March, 1996 - Noise News International

Create successful ePaper yourself

Delete template?

Save as template?