Materials Database

Absorption Coefficients

Massive constructions and hard surfaces

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

hard_surface

Walls, hard surfaces average (brick walls, plaster, hard floors, etc.)

0.02

0.02

0.03

0.03

0.04

0.05

0.05

brickwork

Walls, rendered brickwork

0.01

0.02

0.02

0.03

0.03

0.04

0.04

rough_concrete

Rough concrete

0.02

0.03

0.03

0.03

0.04

0.07

0.07

unpainted_concrete

Smooth unpainted concrete

0.01

0.01

0.02

0.02

0.02

0.05

0.05

rough_lime_wash

Rough lime wash

0.02

0.03

0.04

0.05

0.04

0.03

0.02

smooth_brickwork_flush_pointing

Smooth brickwork with flush pointing, painted

0.01

0.01

0.02

0.02

0.02

0.02

0.02

smooth_brickwork_10mm_pointing

Smooth brickwork, 10 mm deep pointing, pit sand mortar

0.08

0.09

0.12

0.16

0.22

0.24

0.24

brick_wall_rough

Brick wall, stuccoed with a rough finish

0.03

0.03

0.03

0.04

0.05

0.07

0.07

ceramic_tiles

Ceramic tiles with a smooth surface

0.01

0.01

0.01

0.02

0.02

0.02

0.02

limestone_wall

Limestone walls

0.02

0.02

0.03

0.04

0.05

0.05

0.05

reverb_chamber

Reverberation chamber walls

0.01

0.01

0.01

0.02

0.02

0.04

0.04

concrete_floor

Concrete floor

0.01

0.03

0.05

0.02

0.02

0.02

0.02

marble_floor

Marble floor

0.01

0.01

0.01

0.02

0.02

0.02

0.02

Lightweight constructions and linings

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

plasterboard

2 * 13 mm plasterboard on steel frame, 50 mm mineral wool in cavity, surface painted

0.15

0.1

0.06

0.04

0.04

0.05

0.05

wooden_lining

Wooden lining, 12 mm fixed on frame

0.27

0.23

0.22

0.15

0.1

0.07

0.06

Glazing

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

glass_3mm

Single pane of glass, 3 mm

0.08

0.04

0.03

0.03

0.02

0.02

0.02

glass_window

Glass window, 0.68 kg/m2

0.1

0.05

0.04

0.03

0.03

0.03

0.03

lead_glazing

Lead glazing

0.3

0.2

0.14

0.1

0.05

0.05

double_glazing_30mm

Double glazing, 2–3 mm glass, > 30 mm gap

0.15

0.05

0.03

0.03

0.02

0.02

0.02

double_glazing_10mm

Double glazing, 2–3 mm glass, 10 mm gap

0.1

0.07

0.05

0.03

0.02

0.02

0.02

double_glazing_inside

Double glazing, lead on the inside

0.15

0.3

0.18

0.1

0.05

0.05

Wood

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

wood_1.6cm

Wood, 1.6 cm thick, on 4 cm wooden planks

0.18

0.12

0.1

0.09

0.08

0.07

0.07

plywood_thin

Thin plywood panelling

0.42

0.21

0.1

0.08

0.06

0.06

wood_16mm

16 mm wood on 40 mm studs

0.18

0.12

0.1

0.09

0.08

0.07

0.07

audience_floor

Audience floor, 2 layers, 33 mm on sleepers over concrete

0.09

0.06

0.05

0.05

0.05

0.04

stage_floor

Wood, stage floor, 2 layers, 27 mm over airspace

0.1

0.07

0.06

0.06

0.06

0.06

wooden_door

Solid wooden door

0.14

0.1

0.06

0.08

0.1

0.1

0.10

Floor coverings

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

linoleum_on_concrete

Linoleum, asphalt, rubber, or cork tile on concrete

0.02

0.03

0.03

0.03

0.03

0.02

carpet_cotton

Cotton carpet

0.07

0.31

0.49

0.81

0.66

0.54

0.48

carpet_tufted_9.5mm

Loop pile tufted carpet, 1.4 kg/m2, 9.5 mm pile height: On hair pad, 3.0 kg/m2

0.1

0.4

0.62

0.7

0.63

0.88

carpet_thin

Thin carpet, cemented to concrete

0.02

0.04

0.08

0.2

0.35

0.4

carpet_6mm_closed_cell_foam

6 mm pile carpet bonded to closed-cell foam underlay

0.03

0.09

0.25

0.31

0.33

0.44

0.44

carpet_6mm_open_cell_foam

6 mm pile carpet bonded to open-cell foam underlay

0.03

0.09

0.2

0.54

0.7

0.72

0.72

carpet_tufted_9m

9 mm tufted pile carpet on felt underlay

0.08

0.08

0.3

0.6

0.75

0.8

0.80

felt_5mm

Needle felt 5 mm stuck to concrete

0.02

0.02

0.05

0.15

0.3

0.4

0.40

carpet_soft_10mm

10 mm soft carpet on concrete

0.09

0.08

0.21

0.26

0.27

0.37

carpet_hairy

Hairy carpet on 3 mm felt

0.11

0.14

0.37

0.43

0.27

0.25

0.25

carpet_rubber_5mm

5 mm rubber carpet on concrete

0.04

0.04

0.08

0.12

0.1

0.1

carpet_1.35_kg_m2

Carpet 1.35 kg/m2, on hair felt or foam rubber

0.08

0.24

0.57

0.69

0.71

0.73

cocos_fibre_roll_29mm

Cocos fibre roll felt, 29 mm thick (unstressed), reverse side clad with paper, 2.2 kg/m2, 2 Rayl

0.1

0.13

0.22

0.35

0.47

0.57

Curtains

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

curtains_cotton_0.5

Cotton curtains (0.5 kg/m2) draped to 3/4 area approx. 130 mm from wall

0.3

0.45

0.65

0.56

0.59

0.71

0.71

curtains_0.2

Curtains (0.2 kg/m2) hung 90 mm from wall

0.05

0.06

0.39

0.63

0.7

0.73

0.73

curtains_cotton_0.33

Cotton cloth (0.33 kg/m2) folded to 7/8 area

0.03

0.12

0.15

0.27

0.37

0.42

curtains_densely_woven

Densely woven window curtains 90 mm from wall

0.06

0.1

0.38

0.63

0.7

0.73

blinds_half_open

Vertical blinds, 15 cm from wall, half opened (45°)

0.03

0.09

0.24

0.46

0.79

0.76

blinds_open

Vertical blinds, 15 cm from wall, open (90°)

0.03

0.06

0.13

0.28

0.49

0.56

curtains_velvet

Tight velvet curtains

0.05

0.12

0.35

0.45

0.38

0.36

0.36

curtains_fabric

Curtain fabric, 15 cm from wall

0.1

0.38

0.63

0.52

0.55

0.65

curtains_fabric_folded

Curtain fabric, folded, 15 cm from wall

0.12

0.6

0.98

1

1

1

1.00

curtains_glass_mat

Curtains of close-woven glass mat hung 50 mm from wall

0.03

0.03

0.15

0.4

0.5

0.5

0.50

studio_curtains

Studio curtains, 22 cm from wall

0.36

0.26

0.51

0.45

0.62

0.76

Seating (2 seats per m2)

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

chairs_wooden

Wooden chairs without cushion

0.05

0.08

0.1

0.12

0.12

0.12

chairs_unoccupied_plastic

Unoccupied plastic chairs

0.06

0.1

0.1

0.2

0.3

0.2

0.20

chairs_medium_upholstered

Medium upholstered concert chairs, empty

0.49

0.66

0.8

0.88

0.82

0.7

chairs_heavy_upholstered

Heavily upholstered seats, unoccupied

0.7

0.76

0.81

0.84

0.84

0.81

chairs_upholstered_cloth

Empty chairs, upholstered with cloth cover

0.44

0.6

0.77

0.89

0.82

0.7

0.70

chairs_upholstered_leather

Empty chairs, upholstered with leather cover

0.4

0.5

0.58

0.61

0.58

0.5

0.50

chairs_upholstered_moderate

Unoccupied, moderately upholstered chairs (0.90 m × 0.55 m)

0.44

0.56

0.67

0.74

0.83

0.87

Audience (unless not specified explicitly, 2 persons per m2)

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

audience_orchestra_choir

Areas with audience, orchestra or choir including narrow aisles

0.6

0.74

0.88

0.96

0.93

0.85

0.85

audience_wooden_chairs_1_m2

Audience on wooden chairs, 1 per m2

0.16

0.24

0.56

0.69

0.81

0.78

0.78

audience_wooden_chairs_2_m2

Audience on wooden chairs, 2 per m2

0.24

0.4

0.78

0.98

0.96

0.87

0.87

orchestra_1.5_m2

Orchestra with instruments on podium, 1.5 m2 per person

0.27

0.53

0.67

0.93

0.87

0.8

0.80

audience_0.72_m2

Audience area, 0.72 persons / m2

0.1

0.21

0.41

0.65

0.75

0.71

audience_1_m2

Audience area, 1 person / m2

0.16

0.29

0.55

0.8

0.92

0.9

audience_1.5_m2

Audience area, 1.5 persons / m2

0.22

0.38

0.71

0.95

0.99

0.99

audience_2_m2

Audience area, 2 persons / m2

0.26

0.46

0.87

0.99

0.99

0.99

audience_upholstered_chairs_1

Audience in moderately upholstered chairs 0,85 m × 0,63 m

0.72

0.82

0.91

0.93

0.94

0.87

audience_upholstered_chairs_2

Audience in moderately upholstered chairs 0,90 m × 0,55 m

0.55

0.86

0.83

0.87

0.9

0.87

Wall absorbers

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

panel_fabric_covered_6pcf

Fabric-covered panel, 6 pcf rockwool core

0.46

0.93

1

1

1

1

1.00

panel_fabric_covered_8pcf

Fabric-covered panel, 8 pcf rockwool core

0.21

0.66

1

1

0.97

0.98

0.98

facing_brick

Facing-brick brickwork, open butt joins, brick dimensions 230 × 50 × 55 mm

0.04

0.14

0.49

0.35

0.31

0.36

acoustical_plaster_25mm

Acoustical plaster, approx. 25 mm thick, 3.5 kg/m2/cm

0.17

0.36

0.66

0.65

0.62

0.68

rockwool_50mm_80kgm3

Rockwool thickness = 50 mm, 80 kg/m3

0.22

0.6

0.92

0.9

0.88

0.88

0.88

rockwool_50mm_40kgm3

Rockwool thickness = 50 mm, 40 kg/m3

0.23

0.59

0.86

0.86

0.86

0.86

0.86

mineral_wool_50mm_40kgm3

50 mm mineral wool (40 kg/m3), glued to wall, untreated surface

0.15

0.7

0.6

0.6

0.85

0.9

0.90

mineral_wool_50mm_70kgm3

50 mm mineral wool (70 kg/m3) 300 mm in front of wall

0.7

0.45

0.65

0.6

0.75

0.65

0.65

gypsum_board

Gypsum board, perforation 19.6%, hole diameter 15 mm, backed by fibrous web 12 Rayl, 100 mm cavity filled with mineral fibre mat 1,05 kg/m2, 7,5 Rayl

0.3

0.69

1

0.81

0.66

0.62

perforated_veneered_chipboard

Perforated veneered chipboard, 50 mm, 1 mm holes, 3 mm spacing, 9% hole surface ratio, 150 mm cavity filled with 30 mm mineral wool

0.41

0.67

0.58

0.59

0.68

0.35

fibre_absorber_1

Fibre absorber, mineral fibre, 20 mm thick, 3.4 kg/m2, 50 mm cavity

0.2

0.56

0.82

0.87

0.7

0.53

fibre_absorber_2

Fibre absorber, mats of porous flexible fibrous web fabric, self-extinguishing

0.07

0.07

0.2

0.41

0.75

0.97

Ceiling absorbers

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

ceiling_plasterboard

Plasterboard ceiling on battens with large air-space above

0.2

0.15

0.1

0.08

0.04

0.02

ceiling_fibre_abosrber

Fibre absorber on perforated sheet metal cartridge, 0,5 mm zinc-plated steel, 1.5 mm hole diameter, 200 mm cavity filled with 20 mm mineral wool (20 kg/m3), inflammable

0.48

0.97

1

0.97

1

1

1.00

ceiling_fissured_tile

Fissured ceiling tile

0.49

0.53

0.53

0.75

0.92

0.99

ceiling_perforated_gypsum_board

Perforated 27 mm gypsum board (16%), d = 4,5 mm, 300 mm from ceiling

0.45

0.55

0.6

0.9

0.86

0.75

ceiling_melamine_foam

Wedge-shaped, melamine foam, ceiling tile

0.12

0.33

0.83

0.97

0.98

0.95

ceiling_metal_panel

Metal panel ceiling, backed by 20 mm Sillan acoustic tiles, panel width 85 mm, panel spacing 15 mm, cavity 35 cm

0.59

0.8

0.82

0.65

0.27

0.23

Special absorbers

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

microperforated_foil_kaefer

Microperforated foil “Microsorber” (Kaefer)

0.06

0.28

0.7

0.68

0.74

0.53

microperforated_glass_sheets

Microperforated glass sheets, 5 mm cavity

0.1

0.45

0.85

0.3

0.1

0.05

hanging_absorber_panels_1

Hanging absorber panels (foam), 400 mm depth, 400 mm distance

0.25

0.45

0.8

0.9

0.85

0.8

hanging_absorber_panels_2

Hanging absorber panels (foam), 400 mm depth, 700 mm distance

0.2

0.3

0.6

0.75

0.7

0.7

Scattering Coefficients

Diffusers

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

rpg_skyline

Diffuser RPG Skyline

0.01

0.08

0.45

0.82

1

rpg_qrd

Diffuser RPG QRD

0.06

0.15

0.45

0.95

0.88

0.91

Seating and audience

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

theatre_audience

Theatre Audience

0.3

0.5

0.6

0.6

0.7

0.70

0.70

classroom_tables

Rows of classroom tables and persons on chairs

0.2

0.3

0.4

0.5

0.5

0.60

0.60

amphitheatre_steps

Amphitheatre steps, length 82 cm, height 30 cm (Farnetani 2005)

0.05

0.45

0.75

0.9

0.9

Round Robin III – wall and ceiling

keyword

description

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

rect_prism_boxes

Rectangularandprismboxes (studio wall) “Round Robin III” (after (Bork 2005a))

0.5

0.9

0.95

0.95

0.95

0.95

trapezoidal_boxes

Trapezoidal boxes (studio ceiling) “Round Robin III” (after (Bork 2005a))

0.13

0.56

0.95

0.95

0.95

0.95