US2028180A - Acoustic materials - Google Patents
Acoustic materials Download PDFInfo
- Publication number
- US2028180A US2028180A US482678A US48267830A US2028180A US 2028180 A US2028180 A US 2028180A US 482678 A US482678 A US 482678A US 48267830 A US48267830 A US 48267830A US 2028180 A US2028180 A US 2028180A
- Authority
- US
- United States
- Prior art keywords
- frequencies
- energy
- sound
- acoustic
- air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000012814 acoustic material Substances 0.000 title description 4
- 239000000463 material Substances 0.000 description 9
- 238000010521 absorption reaction Methods 0.000 description 7
- 239000011358 absorbing material Substances 0.000 description 6
- 239000010410 layer Substances 0.000 description 6
- 239000011148 porous material Substances 0.000 description 5
- 210000003298 dental enamel Anatomy 0.000 description 3
- 239000003973 paint Substances 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 206010040007 Sense of oppression Diseases 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011505 plaster Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/62—Insulation or other protection; Elements or use of specified material therefor
- E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
- E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
- E04B1/84—Sound-absorbing elements
- E04B1/86—Sound-absorbing elements slab-shaped
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/62—Insulation or other protection; Elements or use of specified material therefor
- E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
- E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
- E04B1/84—Sound-absorbing elements
- E04B2001/8457—Solid slabs or blocks
- E04B2001/8461—Solid slabs or blocks layered
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S264/00—Plastic and nonmetallic article shaping or treating: processes
- Y10S264/63—Processes of molding porous blocks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
- Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
- Y10T442/259—Coating or impregnation provides protection from radiation [e.g., U.V., visible light, I.R., micscheme-change-itemave, high energy particle, etc.] or heat retention thru radiation absorption
Definitions
- This invention relates to the acoustic treatment of walls or partitions of rooms such as sound picture studios and is a continuation in part of my application, Serial No. 248,332 filed January 21,
- the present invention has for its object to provide for substantially uniform absorption of air wave energy over a wide range of frequencies such as those produced by speech and music.
- porous material-one of rather loose texture of low density and easy to compress, with low elastic constant and high internal friction is used in thicknesses ranging from a fraction of an inch to a few inches; usually, however, practical considerations limit the thickness to the order of an inch or less.
- sound waves in air are compression waves in which the air moves forward and back with a variable velocity and between limits determined by the wave-length or frequency of the sound wave.
- the wave-length In the case of sounds with the frequency of 100 cycles per second the wave-length is approximately 11 feet; whereas in the case of sounds of 10,000 cycles per second the wave-length is only a little more than 1 inch.
- the action of the sound absorbing material is to abstract energy from the sound wave either by the internal friction of its own loose structure when moved back and forth by the sound wave, or by the friction between the air itself and the material as the air is driven in and out of its porous structure.
- An efiicient proportion is obtained when the exposed surface layer has a thickness 2% or less of the main absorbing body and a density 3 to5times as great as that of the main body. While these proportions operate to advantage it may be stated as a general principle that the surface layer should be as dense as possible. A layer of gold foil of the order of 1/100 of an inch thickness would be very excellent but is obviously impracticable. A more practical method is to coat the surface of the absorbing material with a plastic or liquid surfacing which sets to a hard, firm surface. Paint or enamel compounded with a heavy base, or a very thin layer of cement or plaster, are practical mediums for realizing the desired advantages.
- I represents a thick, porous and easily compressible layer of low density material such as felt and 2 a hard, smooth surface which for practical purposes may comprise a thin coating 7 of paint or enamel applied in liquid form and thin layer of high density non-porous material covering the porous material to prevent excessive absorption of energy from air waves of the higher frequencies.
- a partition or wall covering for the acoustic treatment of rooms comprising a thick porous material such as felt adapted to absorb energy from air waves of the lower frequencies and an exposed thin layer of high density non-porous material such as paint or enamel'covering the 10 porous material and adapted to prevent excessive absorption of energy from air waves of the higher frequencies.
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Electromagnetism (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Building Environments (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Description
' Jan. 21,1936. H, D ARNQLD 2,028,180
ACOUSTIC MATERIALS Filed Sept. 18, 1930 INVENTOR HDARNOLD Arroagver Patented Jan. 21, 1936 ACOUSTIC MATERIALS Harold D. Arnold, Maplewood, N. J., assignor to Bell Telephone Laboratories,
Incorporated,
New York, N. Y., a corporation of New York App ication September 18, 1930, Serial No. 482,67 8
2 Claims.
This invention relates to the acoustic treatment of walls or partitions of rooms such as sound picture studios and is a continuation in part of my application, Serial No. 248,332 filed January 21,
The present invention has for its object to provide for substantially uniform absorption of air wave energy over a wide range of frequencies such as those produced by speech and music.
To reduce reflections and reverberations it has been customary to surface a room with a thick.
porous material-one of rather loose texture of low density and easy to compress, with low elastic constant and high internal friction. For purposes of convenience, such material is used in thicknesses ranging from a fraction of an inch to a few inches; usually, however, practical considerations limit the thickness to the order of an inch or less.
As is well known, sound waves in air are compression waves in which the air moves forward and back with a variable velocity and between limits determined by the wave-length or frequency of the sound wave. In the case of sounds with the frequency of 100 cycles per second the wave-length is approximately 11 feet; whereas in the case of sounds of 10,000 cycles per second the wave-length is only a little more than 1 inch. The action of the sound absorbing material is to abstract energy from the sound wave either by the internal friction of its own loose structure when moved back and forth by the sound wave, or by the friction between the air itself and the material as the air is driven in and out of its porous structure.
It is desirable to have an acoustic material which will abstract the same percentage of its energy from any sound wave no matter what its frequency. That this i not accomplished by materials such as felt, Celotex, and others commonly used, is plainly evident upon entering a room surfaced with these materials. Such rooms give a sense of oppression which careful analysis shows is due to the undue absorption of high frequency sound waves. This results in too great a relative emphasis of the low pitched sounds with a loss of that clearness and sharpness of acoustic effects which require the retention of high frequencies. The reason for this undesirably large relative absorption of high frequencies is that the materials as used are so thin in comparision with the large extent of movement in. low frequency sound waves, as described above, that they are not very effective in abstracting energy from such sounds. This elation is, however. enormously dilferent with reference to very high pitched sounds and hence they are more effective as absorbers of these latter sounds.
Attempts to correct this situation and provide a better absorbing material might follow either of two lines, one of which would be to make the material a better absorber of low frequencies. This, however, would entail an abnormal increase in the thickness of the material used or a change in its internal structure and is not attempted here. The other is to provide a structure in which the absorption of sound energy at the high frequencies is reduced until it is comparable with the absorption at low frequencies. It is my in vention to accomplish this by applying to the exposed surface of the absorbing material a thin, non-porous layer of high density material. This allows the thick mass of the absorbing material proper to compress and expand with the low frequency sound waves, thus abstracting energy from them by its internal friction. It does not, however, allow such movements to a corresponding extent with high frequency sound waves, since their reflection will be determined to a large extent by the heavy surface they first meet and through which they cannot so readily communicate.
Experiment has shown that the addition of such a thin dense coating to the surface of a sound absorbing material such as Celotex or felt does effectively decrease the absorbing power at high frequencies without making such a substantial reduction at low frequencies and therefore produces a more uniform coeflicient through the entire frequency range.
An efiicient proportion is obtained when the exposed surface layer has a thickness 2% or less of the main absorbing body and a density 3 to5times as great as that of the main body. While these proportions operate to advantage it may be stated as a general principle that the surface layer should be as dense as possible. A layer of gold foil of the order of 1/100 of an inch thickness would be very excellent but is obviously impracticable. A more practical method is to coat the surface of the absorbing material with a plastic or liquid surfacing which sets to a hard, firm surface. Paint or enamel compounded with a heavy base, or a very thin layer of cement or plaster, are practical mediums for realizing the desired advantages.
In the drawing which is a sectional view of a wall covering made in accordance with my invention, I represents a thick, porous and easily compressible layer of low density material such as felt and 2 a hard, smooth surface which for practical purposes may comprise a thin coating 7 of paint or enamel applied in liquid form and thin layer of high density non-porous material covering the porous material to prevent excessive absorption of energy from air waves of the higher frequencies.
2. A partition or wall covering for the acoustic treatment of rooms comprising a thick porous material such as felt adapted to absorb energy from air waves of the lower frequencies and an exposed thin layer of high density non-porous material such as paint or enamel'covering the 10 porous material and adapted to prevent excessive absorption of energy from air waves of the higher frequencies.
' HAROLD D. ARNOLD. l5
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US482678A US2028180A (en) | 1930-09-18 | 1930-09-18 | Acoustic materials |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US482678A US2028180A (en) | 1930-09-18 | 1930-09-18 | Acoustic materials |
Publications (1)
Publication Number | Publication Date |
---|---|
US2028180A true US2028180A (en) | 1936-01-21 |
Family
ID=23916993
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US482678A Expired - Lifetime US2028180A (en) | 1930-09-18 | 1930-09-18 | Acoustic materials |
Country Status (1)
Country | Link |
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US (1) | US2028180A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2502018A (en) * | 1944-03-30 | 1950-03-28 | Rca Corp | Diffraction type sound absorber covered by a membrane |
US2562711A (en) * | 1948-02-25 | 1951-07-31 | Interchem Corp | Method of producing heat and sound insulation |
US2566975A (en) * | 1947-01-18 | 1951-09-04 | Leo L Beranek | Voice silencer |
US3111188A (en) * | 1960-02-26 | 1963-11-19 | Owens Corning Fiberglass Corp | Acoustical tile |
US3122216A (en) * | 1960-03-21 | 1964-02-25 | Owens Corning Fiberglass Corp | Acoustical ceiling panels |
US3182747A (en) * | 1954-04-09 | 1965-05-11 | Holzwerke H Wilheimi Fa | Sound absorbing micro-porous wall panel structures |
US3239973A (en) * | 1964-01-24 | 1966-03-15 | Johns Manville | Acoustical glass fiber panel with diaphragm action and controlled flow resistance |
-
1930
- 1930-09-18 US US482678A patent/US2028180A/en not_active Expired - Lifetime
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2502018A (en) * | 1944-03-30 | 1950-03-28 | Rca Corp | Diffraction type sound absorber covered by a membrane |
US2566975A (en) * | 1947-01-18 | 1951-09-04 | Leo L Beranek | Voice silencer |
US2562711A (en) * | 1948-02-25 | 1951-07-31 | Interchem Corp | Method of producing heat and sound insulation |
US3182747A (en) * | 1954-04-09 | 1965-05-11 | Holzwerke H Wilheimi Fa | Sound absorbing micro-porous wall panel structures |
US3111188A (en) * | 1960-02-26 | 1963-11-19 | Owens Corning Fiberglass Corp | Acoustical tile |
US3122216A (en) * | 1960-03-21 | 1964-02-25 | Owens Corning Fiberglass Corp | Acoustical ceiling panels |
US3239973A (en) * | 1964-01-24 | 1966-03-15 | Johns Manville | Acoustical glass fiber panel with diaphragm action and controlled flow resistance |
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