US2881850A - Infinite baffle comprising a spherical shell of foamed plastic - Google Patents
Infinite baffle comprising a spherical shell of foamed plastic Download PDFInfo
- Publication number
- US2881850A US2881850A US524055A US52405555A US2881850A US 2881850 A US2881850 A US 2881850A US 524055 A US524055 A US 524055A US 52405555 A US52405555 A US 52405555A US 2881850 A US2881850 A US 2881850A
- Authority
- US
- United States
- Prior art keywords
- loudspeaker
- foamed plastic
- shell
- spherical shell
- speaker
- 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
- 239000004033 plastic Substances 0.000 title description 8
- 210000004027 cell Anatomy 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000033458 reproduction Effects 0.000 description 2
- 239000011324 bead Substances 0.000 description 1
- 210000003850 cellular structure Anatomy 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 229920006248 expandable polystyrene Polymers 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical class 0.000 description 1
- 230000026683 transduction Effects 0.000 description 1
- 238000010361 transduction Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only
- H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
- H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
- H04R1/2884—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of the enclosure structure, i.e. strengthening or shape of the enclosure
- H04R1/2888—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of the enclosure structure, i.e. strengthening or shape of the enclosure for loudspeaker transducers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only
- H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
- H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
- H04R1/2876—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of damping material, e.g. as cladding
- H04R1/288—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of damping material, e.g. as cladding for loudspeaker transducers
Definitions
- My invention relates to an acoustic device, and more particularly relates to an acoustic housing for a loud speaker.
- loudspeakers have been mounted upon various types of sounding boards in order to provide a resonant quality to the tone produced by the speaker.
- These sounding boards have been made of Wood and also of plastic, and many shapes and veneers have been employed in order to match the vibrant characteristics of the particular size loudspeaker.
- intricate baffling arrangements involving considerable cabinet work are necessary to impart to a loudspeaker high fidelity and high efficiency characteristics.
- Another object of my invention is to provide a portable acoustic housing device for a loudspeaker which will afford high quality transduction of electrical energy to acoustical energy in a wide variety of mounting positions and with a wide range of loudspeaker sizes.
- Another object of my invention is to provide an attractive and simple acoustic device which is molded of light weight plastic and requires no independent sounding board.
- Fig. 1 is a perspective view of an acoustic device embodying my invention.
- Fig. 2 is a sectional view taken along lines 22 of Fig. 1.
- Fig. 3 is a perspective view of a molded hemispherical shell before bonding to form the acoustic housing.
- I show an acoustic housing, generally designated as A, and a loudspeaker, generally designated as B.
- the acoustic housing A shown in Fig. 1, comprises a pair of hemispherical shells A1 which have been connected so as to define a hollow sphere having a chamber 18.
- the embodiment in the drawing is spherical in shape, the surface characteristics may be ellipsoidal or multi-faceted.
- Each shell A1 is fabricated of foam plastic such as an isocyanate plastic or expandable polystyrene beads molded in a cavity in the presence of suitable reactive agents to form a discrete, closed cell, foamed structure having a smooth surfaced inner skin 10 and outer skin 12.
- foam plastic such as an isocyanate plastic or expandable polystyrene beads molded in a cavity in the presence of suitable reactive agents to form a discrete, closed cell, foamed structure having a smooth surfaced inner skin 10 and outer skin 12.
- the density of the molded shell ranges from 4 to 6 pounds per cubic foot.
- the acoustic housing A is cored to form an opening adapted to receive the loudspeaker unit.
- the loudspeaker B is a conventional electro-magnetic coil or permanent magnet type speaker and is mounted flush or recessed within the outer surface 12 by a plurality of mounting screws 14 over the opening in the housing A.
- speaker may be mounted upon a rigid ring or supporting frame which, in turn, is mounted directly upon the shell of the acoustic housing.
- the housing for the loudspeaker should be directly coupled with the shell of the sphere and in rigid contact therewith to be most favorably effective for producing true loudspeaker reproductions of signals.
- Figs. 1 and 2 I show the acoustic device A mounted upon a plurality of legs 16.
- the housing A may 20 be suspended from the ceiling by guy wires or be laid directly upon the floor.
- the structure of the acoustic shelf is a plurality of non-communictting hollow cells.
- Thesmooth interior skin 10 reflects sound from the rear of 5 the speaker into the center of the hollow interior chamber 18 while the discrete closed cellular structure of the shell. absorbs any audible sounds which otherwise would pass: through the shell itself.
- the enclosed air space in the chamber 18 acts as a damping medium and effectively cancels sound waves created within the chamber by the loudspeaker, thereby nullifying any harmonic disturbances reflected toward the back of the speaker.
- My theory of operation is that sound is generated from the front and the back of the loud speaker, but 180 out of phase.
- the function of the soundboard which in this case is the sphere, is to isolate and cancel this rear emanating sound which otherwise would escape and cancel out the front emanating sound. Since any interior sound is damped, the sound emitted exteriorly by the speaker is the true reproduction of electrical impulses imposed upon the speaker.
- an acoustic device comprising a molded, foamed plastic spherical shell, said shell being of a closed multi-cellular structure and having a smooth inner skin and a smooth outer skin, and means to mount the loudspeaker directly and rigidly to said shell within a complementary aperture therein, said shell defining an infinite bafile whereby a high fidelity enclosure will result to yield a flattened frequency response curve for sound emanating from the loudspeaker.
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- Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Details Of Audible-Bandwidth Transducers (AREA)
Description
Apnl 14, 1959 L. BONN 2, INFINITE BAFFLE COMPRISING A SPHERICAL saw. OF FOAMED PLASTIC Filed July 25, 1955 INVENTOR.
LEONARD BONN BY ATTORNEY FIG. 3
United States Patent INFINITE BAFFLE COMPRISING A SPHERICAL SHELL OF FOAMED PLASTIC Leonard Bonn, Philadelphia, Pa. Application July 25, 1955, Serial No. 524,055 1 Claim. (Cl.- 181-31) My invention relates to an acoustic device, and more particularly relates to an acoustic housing for a loud speaker.
Heretofore, loudspeakers have been mounted upon various types of sounding boards in order to provide a resonant quality to the tone produced by the speaker. These sounding boards have been made of Wood and also of plastic, and many shapes and veneers have been employed in order to match the vibrant characteristics of the particular size loudspeaker. However, it is well recognized that intricate baffling arrangements involving considerable cabinet work are necessary to impart to a loudspeaker high fidelity and high efficiency characteristics.
It, therefore, is an object of my invention to provide an acoustic housing device for a loudspeaker which will impart high fidelity characteristics at higher levels of efliciency.
Another object of my invention is to provide a portable acoustic housing device for a loudspeaker which will afford high quality transduction of electrical energy to acoustical energy in a wide variety of mounting positions and with a wide range of loudspeaker sizes.
Another object of my invention is to provide an attractive and simple acoustic device which is molded of light weight plastic and requires no independent sounding board.
Other objects of my invention are to provide an improved device of the character described, that is easily and economically produced, which is sturdy in construction, and which is highly effective in operation.
With the above and related objects in view, my invention consists in the details of construction and combination of parts, as will be more fully understood from the following description when read in conjunction with the accompanying drawing, in which:
Fig. 1 is a perspective view of an acoustic device embodying my invention.
Fig. 2 is a sectional view taken along lines 22 of Fig. 1.
Fig. 3 is a perspective view of a molded hemispherical shell before bonding to form the acoustic housing.
Referring now in greater detail to the drawing, in which similar reference characters refer to similar parts, I show an acoustic housing, generally designated as A, and a loudspeaker, generally designated as B.
The acoustic housing A, shown in Fig. 1, comprises a pair of hemispherical shells A1 which have been connected so as to define a hollow sphere having a chamber 18. Although the embodiment in the drawing is spherical in shape, the surface characteristics may be ellipsoidal or multi-faceted.
Each shell A1 is fabricated of foam plastic such as an isocyanate plastic or expandable polystyrene beads molded in a cavity in the presence of suitable reactive agents to form a discrete, closed cell, foamed structure having a smooth surfaced inner skin 10 and outer skin 12. The density of the molded shell ranges from 4 to 6 pounds per cubic foot.
The acoustic housing A is cored to form an opening adapted to receive the loudspeaker unit. The loudspeaker B is a conventional electro-magnetic coil or permanent magnet type speaker and is mounted flush or recessed within the outer surface 12 by a plurality of mounting screws 14 over the opening in the housing A. The
speaker may be mounted upon a rigid ring or supporting frame which, in turn, is mounted directly upon the shell of the acoustic housing. The housing for the loudspeaker should be directly coupled with the shell of the sphere and in rigid contact therewith to be most favorably effective for producing true loudspeaker reproductions of signals.
While any diameter speaker commensurate with the diameter of the housing A may be used, the larger the ratio of the housing to speaker diameter, the better is the result. It has been found that a speaker of approximately eight inch diameter attached to an acoustic housing eighteen inches in diameter produces exceptional fidelity with a good quality amplifying system.
In Figs. 1 and 2, I show the acoustic device A mounted upon a plurality of legs 16. However, the housing A may 20 be suspended from the ceiling by guy wires or be laid directly upon the floor.
It is to be noted that the structure of the acoustic shelf is a plurality of non-communictting hollow cells. Thesmooth interior skin 10 reflects sound from the rear of 5 the speaker into the center of the hollow interior chamber 18 while the discrete closed cellular structure of the shell. absorbs any audible sounds which otherwise would pass: through the shell itself. The enclosed air space in the chamber 18 acts as a damping medium and effectively cancels sound waves created within the chamber by the loudspeaker, thereby nullifying any harmonic disturbances reflected toward the back of the speaker. My theory of operation is that sound is generated from the front and the back of the loud speaker, but 180 out of phase. The function of the soundboard, which in this case is the sphere, is to isolate and cancel this rear emanating sound which otherwise would escape and cancel out the front emanating sound. Since any interior sound is damped, the sound emitted exteriorly by the speaker is the true reproduction of electrical impulses imposed upon the speaker.
Although my invention has been described in considerable detail, such description is intended as being illustrative rather than limiting, since the invention may be variously embodied, and the scope of the invention is to be determined as claimed.
I claim as my invention:
'In combination with a loudspeaker, an acoustic device comprising a molded, foamed plastic spherical shell, said shell being of a closed multi-cellular structure and having a smooth inner skin and a smooth outer skin, and means to mount the loudspeaker directly and rigidly to said shell within a complementary aperture therein, said shell defining an infinite bafile whereby a high fidelity enclosure will result to yield a flattened frequency response curve for sound emanating from the loudspeaker.
References Cited in the file of this patent UNITED STATES PATENTS 2,138,717 Volk Nov. 29, 1938 FOREIGN PATENTS 510,707 Great Britain Aug. 4, 1939 653,263 Great Britain May 9, 1951
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US524055A US2881850A (en) | 1955-07-25 | 1955-07-25 | Infinite baffle comprising a spherical shell of foamed plastic |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US524055A US2881850A (en) | 1955-07-25 | 1955-07-25 | Infinite baffle comprising a spherical shell of foamed plastic |
Publications (1)
Publication Number | Publication Date |
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US2881850A true US2881850A (en) | 1959-04-14 |
Family
ID=24087569
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US524055A Expired - Lifetime US2881850A (en) | 1955-07-25 | 1955-07-25 | Infinite baffle comprising a spherical shell of foamed plastic |
Country Status (1)
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US (1) | US2881850A (en) |
Cited By (27)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3026955A (en) * | 1956-08-23 | 1962-03-27 | Howard L Wilber | Spherical loudspeaker enclosure |
US3026956A (en) * | 1957-10-17 | 1962-03-27 | Howard L Wilber | Detachable spherical loudspeaker enclosure |
US3285364A (en) * | 1965-06-01 | 1966-11-15 | Ling Temco Vought Inc | Loudspeaker construction |
US3470976A (en) * | 1967-12-11 | 1969-10-07 | Procter Brevard | High fidelity speaker |
US3905447A (en) * | 1973-10-29 | 1975-09-16 | Hammond Corp | Low inertia tremolo unit |
US4057689A (en) * | 1973-07-09 | 1977-11-08 | Roy H. Smith, Jr. | High fidelity sound reproduction system and modules thereof |
US4167985A (en) * | 1976-05-13 | 1979-09-18 | Dunlavy John H | Speaker system |
US4281738A (en) * | 1978-04-17 | 1981-08-04 | Michael Jackson | Spherical loudspeaker enclosure |
US4805729A (en) * | 1987-07-14 | 1989-02-21 | Wascom Bart A | Speaker enclosure |
US4865153A (en) * | 1986-06-23 | 1989-09-12 | Sasaki Glass Co., Ltd. | Speaker system |
US4964482A (en) * | 1989-02-23 | 1990-10-23 | Meyer John E | Loudspeaker enclosure |
US20080308344A1 (en) * | 2007-06-13 | 2008-12-18 | Altec Lansing, A Division Of Plantronics, Inc. | Asymmetric and continuously curved speaker driver enclosure to optimize audio fidelity |
US20140044299A1 (en) * | 2010-11-23 | 2014-02-13 | Daniel Dumay | High fidelty electro-acoustic enclosure and method of manufacture |
USD733690S1 (en) * | 2013-10-30 | 2015-07-07 | Kaotica Corporation | Noise mitigating microphone attachment |
US9118989B2 (en) | 2012-09-05 | 2015-08-25 | Kaotica Corporation | Noise mitigating microphone attachment |
USD757685S1 (en) * | 2014-06-24 | 2016-05-31 | Gwan Woo Park | Sound amplifier |
US20160354954A1 (en) * | 2015-06-03 | 2016-12-08 | Novation Iq Llc | System and method for making hollow foam balls and other molded objects |
USD789906S1 (en) * | 2015-12-11 | 2017-06-20 | Shenzhen Qianhai Headfree Tech. Co., Ltd. | Wireless rechargeable audio device |
USD793363S1 (en) * | 2016-02-06 | 2017-08-01 | Shenzhen Initiative Technology Co., Ltd. | Sound box |
USD813841S1 (en) * | 2017-02-03 | 2018-03-27 | Kyle H. Robinson | Speaker |
USD822647S1 (en) * | 2016-06-27 | 2018-07-10 | Zylia Spolka Z Ograniczona Odpowiedzialnoscia | Microphone |
USD859411S1 (en) * | 2016-08-01 | 2019-09-10 | Hand Held Products, Inc. | Optical scanner |
USD884668S1 (en) * | 2018-04-27 | 2020-05-19 | Samsung Electronics Co., Ltd. | Speaker |
USD890122S1 (en) * | 2018-08-30 | 2020-07-14 | DigiOrange Inc. | Pair of wireless earbuds |
USD990457S1 (en) * | 2020-05-27 | 2023-06-27 | Amazon Technologies, Inc. | Earbud tip |
USD1025011S1 (en) * | 2022-12-13 | 2024-04-30 | Wuxi Future Mirror Display Technology Co., Ltd. | Loudspeaker |
USD1032605S1 (en) * | 2021-08-16 | 2024-06-25 | SecureXperts Incorporated | Cryptographic key generator |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2138717A (en) * | 1936-10-22 | 1938-11-29 | Joseph A Volk | Speaker baffle ball |
GB510707A (en) * | 1937-02-15 | 1939-08-04 | Ig Farbenindustrie Ag | Loud-speaker diaphragm |
GB653263A (en) * | 1947-10-30 | 1951-05-09 | C M C Switchmatic Ltd | Improvements in mountings for loudspeakers |
-
1955
- 1955-07-25 US US524055A patent/US2881850A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2138717A (en) * | 1936-10-22 | 1938-11-29 | Joseph A Volk | Speaker baffle ball |
GB510707A (en) * | 1937-02-15 | 1939-08-04 | Ig Farbenindustrie Ag | Loud-speaker diaphragm |
GB653263A (en) * | 1947-10-30 | 1951-05-09 | C M C Switchmatic Ltd | Improvements in mountings for loudspeakers |
Cited By (33)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3026955A (en) * | 1956-08-23 | 1962-03-27 | Howard L Wilber | Spherical loudspeaker enclosure |
US3026956A (en) * | 1957-10-17 | 1962-03-27 | Howard L Wilber | Detachable spherical loudspeaker enclosure |
US3285364A (en) * | 1965-06-01 | 1966-11-15 | Ling Temco Vought Inc | Loudspeaker construction |
US3470976A (en) * | 1967-12-11 | 1969-10-07 | Procter Brevard | High fidelity speaker |
US4057689A (en) * | 1973-07-09 | 1977-11-08 | Roy H. Smith, Jr. | High fidelity sound reproduction system and modules thereof |
US3905447A (en) * | 1973-10-29 | 1975-09-16 | Hammond Corp | Low inertia tremolo unit |
US4167985A (en) * | 1976-05-13 | 1979-09-18 | Dunlavy John H | Speaker system |
US4281738A (en) * | 1978-04-17 | 1981-08-04 | Michael Jackson | Spherical loudspeaker enclosure |
US4865153A (en) * | 1986-06-23 | 1989-09-12 | Sasaki Glass Co., Ltd. | Speaker system |
US4805729A (en) * | 1987-07-14 | 1989-02-21 | Wascom Bart A | Speaker enclosure |
US4964482A (en) * | 1989-02-23 | 1990-10-23 | Meyer John E | Loudspeaker enclosure |
US20080308344A1 (en) * | 2007-06-13 | 2008-12-18 | Altec Lansing, A Division Of Plantronics, Inc. | Asymmetric and continuously curved speaker driver enclosure to optimize audio fidelity |
US7604091B2 (en) * | 2007-06-13 | 2009-10-20 | Plantronics, Inc. | Asymmetric and continuously curved speaker driver enclosure to optimize audio fidelity |
US9210490B2 (en) * | 2010-11-23 | 2015-12-08 | Daniel Dumay | High fidelty electro-acoustic enclosure and method of manufacture |
US20140044299A1 (en) * | 2010-11-23 | 2014-02-13 | Daniel Dumay | High fidelty electro-acoustic enclosure and method of manufacture |
US9118989B2 (en) | 2012-09-05 | 2015-08-25 | Kaotica Corporation | Noise mitigating microphone attachment |
USD733690S1 (en) * | 2013-10-30 | 2015-07-07 | Kaotica Corporation | Noise mitigating microphone attachment |
USD887399S1 (en) | 2013-10-30 | 2020-06-16 | Kaotica Corporation, Corporation #2015091974 | Noise mitigating microphone attachment |
USD817935S1 (en) | 2013-10-30 | 2018-05-15 | Kaotica Corporation, Corporation # 2015091974 | Noise mitigating microphone attachment |
USD757685S1 (en) * | 2014-06-24 | 2016-05-31 | Gwan Woo Park | Sound amplifier |
US20160354954A1 (en) * | 2015-06-03 | 2016-12-08 | Novation Iq Llc | System and method for making hollow foam balls and other molded objects |
US9878474B2 (en) * | 2015-06-03 | 2018-01-30 | Novation Iq Llc | System and method for making hollow foam balls and other molded objects |
USD789906S1 (en) * | 2015-12-11 | 2017-06-20 | Shenzhen Qianhai Headfree Tech. Co., Ltd. | Wireless rechargeable audio device |
USD793363S1 (en) * | 2016-02-06 | 2017-08-01 | Shenzhen Initiative Technology Co., Ltd. | Sound box |
USD822647S1 (en) * | 2016-06-27 | 2018-07-10 | Zylia Spolka Z Ograniczona Odpowiedzialnoscia | Microphone |
USD881886S1 (en) | 2016-08-01 | 2020-04-21 | Hand Held Products, Inc. | Optical scanner |
USD859411S1 (en) * | 2016-08-01 | 2019-09-10 | Hand Held Products, Inc. | Optical scanner |
USD813841S1 (en) * | 2017-02-03 | 2018-03-27 | Kyle H. Robinson | Speaker |
USD884668S1 (en) * | 2018-04-27 | 2020-05-19 | Samsung Electronics Co., Ltd. | Speaker |
USD890122S1 (en) * | 2018-08-30 | 2020-07-14 | DigiOrange Inc. | Pair of wireless earbuds |
USD990457S1 (en) * | 2020-05-27 | 2023-06-27 | Amazon Technologies, Inc. | Earbud tip |
USD1032605S1 (en) * | 2021-08-16 | 2024-06-25 | SecureXperts Incorporated | Cryptographic key generator |
USD1025011S1 (en) * | 2022-12-13 | 2024-04-30 | Wuxi Future Mirror Display Technology Co., Ltd. | Loudspeaker |
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