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