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MECHANICS OF SOUND ABSORPTION

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Presentation on theme: "MECHANICS OF SOUND ABSORPTION"— Presentation transcript:

1 MECHANICS OF SOUND ABSORPTION
INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS MECHANICS OF SOUND ABSORPTION

2 FIBER GLASS BATT INSULATION
SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS DESCRIPTION: ABSORBS BY THE FRICTIONAL DRAG PRODUCED BY MOVING THE AIR IN SMALL SPACES WITHIN THE MATERIAL. FIBER GLASS BATT INSULATION

3 SOUND ABSORPTION ABSORPTION DETERMINED BY: INTRODUCTION
SOUND ABSORBING TREATMENT FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS ABSORPTION DETERMINED BY: THICKNESS POROSITY AIR PATH MUST EXTEND FROM ONE SIDE TO THE OTHER. FIBROUS MATERIALS

4 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS FIBROUS MATERIALS

5 FIBROUS MATERIALS WITH AIR SPACE BEHIND
SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS FIBROUS MATERIALS WITH AIR SPACE BEHIND

6 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS FIBROUS MATERIALS

7 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS FIBROUS MATERIALS

8 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS FIBROUS MATERIALS

9 SOUND ABSORPTION DESCRIPTION: INTRODUCTION SOUND ABSORBING TREATMENT
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS DESCRIPTION: BUILT WITH A MEMBRANE SUCH AS PLYWOOD IN FRONT OF A SEALED AIR SPACE . THE PANEL IS SET IN MOTION BY THE ALTERNATING PRESSURE OF THE IMPINGING SOUND WAVE. THE SOUND WAVE IS CONVERTED INTO HEAT THROUGH INTERNAL VISCOUS DAMPING. PANEL RESONATORS

10 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS PANEL RESONATORS

11 SOUND ABSORPTION APPLICATION:
INTRODUCTION SOUND ABSORBING TREATMENT FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS APPLICATION: USED WHERE EFFICIENT LOW-FREQUENCY ABSORPTION IS REQUIRED AND MIDDLE- AND HIGH-FREQUENCY ABSORPTION IS UNWANTED OR PROVIDED BY ANOTHER TREATMENT. PANEL RESONATORS

12 SOUND ABSORPTION DESCRIPTION: INTRODUCTION SOUND ABSORBING TREATMENT
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS DESCRIPTION: AIR CAVITY WITHIN A MASSIVE ENCLOSURE, CONNECTED TO THE SURROUNDINGS BY A NARROW NECK OPENING. HELMHOLTZ RESONATORS

13 SOUND ABSORPTION METHOD OF ABSORPTION:
INTRODUCTION SOUND ABSORBING TREATMENT FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS METHOD OF ABSORPTION: THE IMPINGING SOUND CAUSES THE AIR IN THE NECK TO VIBRATE & THE MASS BEHIND CAUSES THE ENTIRE CONSTRUCTION TO RESONATE AT A PARTICULAR FREQUENCY. AT THAT FREQUENCY ABSORPTION IS VERY HIGH & DROPS SHARPLY ABOVE AND BELOW THIS FREQUENCY. HELMHOLTZ RESONATOR

14 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS HELMHOLTZ RESONATOR

15 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS HELMHOLTZ RESONATOR

16 SOUND ABSORPTION APPLICATION: INTRODUCTION SOUND ABSORBING TREATMENT
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS APPLICATION: EXTREMELY USEFUL WHEN A SINGLE MAJOR FREQUENCY IS PRESENT. USED IN: GYMNASIUMS SWIMMING POOLS BOWLING LANES INDUSTRIAL BUILDINGS MECHANICAL ROOMS HELMHOLTZ RESONATOR

17 SOUND ABSORPTION DESCRIPTION: INTRODUCTION SOUND ABSORBING TREATMENT
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS DESCRIPTION: PERFORATED FACINGS WHICH ARE SOMEWHAT TRANSPARENT TO SOUND. THEY ARE SOMETIMES PLACED IN FRONT OF A SOUND ABSORBING MATERIAL TO PROTECT OR CONCEAL IT. TRANSONDENT FACINGS

18 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS TRANSONDENT FACINGS

19 SOUND ABSORPTION EVALUATION: INTRODUCTION SOUND ABSORBING TREATMENT
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS EVALUATION: FACINGS TEND TO REDUCE THE EFFECTIVENESS OF SOUND-ABSORBING MATERIALS BY REFLECTING HIGH-FREQUENCY SOUND WAVES. TRANSONDENT FACINGS

20 SOUND ABSORPTION EVALUATION: INTRODUCTION SOUND ABSORBING TREATMENT
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS EVALUATION: IN GENERAL, THE LOWER THE PERCENTAGE OF OPEN AREA IN THE FACING , THE LESS ABSORPTION OF HIGH-FREQUENCY SOUND. TRANSONDENT FACINGS

21 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS TRANSONDENT FACINGS

22 SOUND ABSORPTION LABORATORY TEST MOUNTINGS: INTRODUCTION
SOUND ABSORBING TREATMENT FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS LABORATORY TEST MOUNTINGS: LABORATORY TESTS TO DETERMINE ABSORPTION EFFICIENCY ARE DONE ON A NUMBER OF DIFFERENT MOUNTINGS. MOUNTINGS A, B, D, AND E APPLY TO MOST PREFABRICATED PRODUCTS. TYPE “F” APPLIES TO SOUND-ABSORBING MECHANICAL AIR-DUCTS AND “C” IS USED FOR SPECIAL APPLICATIONS. TEST MOUNTINGS

23 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
FIBROUS MATERIALS PANEL RESONATORS HELMHOLTZ RESONATORS TRANSONDENT FACINGS TEST MOUNTINGS APPLICATIONS TEST MOUNTINGS

24 REVERBERATION CONTROL
SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL REVERBERATION CONTROL

25 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL REVERBERANT FIELD

26 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL REVERBERANT FIELD

27 NR = 10 LOG A2/A1 SOUND ABSORPTION INTRODUCTION
SOUND ABSORBING TREATMENT APPLICATIONS REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL NR = 10 LOG A2/A1 NOISE REDUCTION

28 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL SAMPLE PROBLEM

29 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL SAMPLE PROBLEM

30 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL SAMPLE PROBLEM

31 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL SAMPLE PROBLEM #2

32 NOISE REDUCTION IN LOW CEILINGED SPACES
SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL NOISE REDUCTION IN LOW CEILINGED SPACES

33 NOISE REDUCTION IN HIGH CEILINGED SPACES
SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL NOISE REDUCTION IN HIGH CEILINGED SPACES

34 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL ECHO CONTROL

35 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL ECHO CONTROL

36 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL ECHO CONTROL

37 SOUND ABSORPTION INTRODUCTION SOUND ABSORBING TREATMENT APPLICATIONS
REVERBERATION CONTROL ROOM NOISE REDUCTION ECHO CONTROL ECHO CONTROL


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