US2979149A - Loudspeaker apparatus - Google Patents

Loudspeaker apparatus Download PDF

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Publication number
US2979149A
US2979149A US458650A US45865054A US2979149A US 2979149 A US2979149 A US 2979149A US 458650 A US458650 A US 458650A US 45865054 A US45865054 A US 45865054A US 2979149 A US2979149 A US 2979149A
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Prior art keywords
loudspeaker
sound
casing
room
high frequency
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Expired - Lifetime
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US458650A
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English (en)
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Carlsson Stig
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    • 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
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H04R1/323—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only for loudspeakers

Definitions

  • the present invention concerns the distribution of the sound from the loudspeaker but it also influences the generation of the sound by increasing the acoustic efficiency of the loudspeaker at low audio frequencies.
  • Another object of this invention is to increase the acoustic eflicienoy of the loudspeaker at low audio frequencies.
  • Still another object of the invention is to obtain the two aims above, without bulky arrangements, simply by making the loudspeaker use the characteristics of the listening-room efficiently.
  • the subject of this invention is the configuration of the loudspeaker apparatus as regards the location and direction of its sound-radiating surfaces.
  • the principle of the invention is to make the loudspeaker such that it uses the adjacent surfaces of the listening-room (wall or walls, floor and/or ceiling) as integral parts of the loudspeaker system in such a way that the following two effects are achieved:
  • a preferred embodiment of the invention comprises a loudspeaker assembly comprising two or more sound radiating units of which at least one radiates a low frequency range, and at least one radiates a high frequency range.
  • Each unit may include one or more loudspeaker mechanisms or resonator ports.
  • the high frequency unit may also include a reflector arrangement.
  • the assembly is so designed that the sound radiating units are horizontally displaced relative to each other and that the apparatus may be placed in such a relation to adjoining surfaces of the enclosure or listening-room, that the center of radiation of the low frequency radiating stem ice
  • a listener receives at least one reflected soundaudio frequency radiating unit to that room surface; if
  • the apparatus comprises a reflector arrangement the distance from said high frequency radiating unit is to be measured via the center of gravity of the reflector sur face.
  • the reflected sound pressure waves from the adjoining surfaces of the room added in phase or near in phase to the direct sound pressure from the loudspeaker, increase the acoustic efficiency of the loudspeaker.
  • the listener due to the reflections from the adjacent surfaces of the room, the listener, in addition to the direct sound from the loudspeaker, receives sound from directions other than that of the direct sound and of almost the same intensity.
  • the distance between low frequency sound radiating units and high frequency sound radiating units can be made rather great, and yet the unity of the sound source impression is well preserved.
  • the upper limiting frequency of these effects will be higher the shorter the distance between said radiating surfaces or openings and the adjacent surfaces of the room. Said limiting frequency may easily be raised above 200 c.p.s., and in some cases it may be raised above 500 c.p.s.
  • the Wave-length of sound is of the same order or less than the dimensions of the sound radiating surfaces and the head of the listener. This causes the radiation of the sound radiating surfaces to be directed, and it also affects the hearing of the listener because the intensity of the sound pressure varies around the head of the listener due to the sound field disturbance of the head.
  • the directivity of the sound radiating surfaces is reduced by using a plurality of sound radiating surfaces oriented in different directions. Such directivity is reduced still more if the radiation from said high frequency sound radiating surfaces is reflected at the adjacent surfaces of the room, thus increasing the effective number of sound radiating surfaces due to image phenomena. Both measures contribute to a more uniform distribution of the sound energy radiated. By locating these high frequency sound radiating surfaces at some distance spaced from each other, and the listener will receive the sound radiation from different directions. This reduces the directivity of the listeners aural sensation.
  • FIG. 1 is a perspective view of a loudspeaker apparatus.
  • Fig. 2 shows the external bottom surface of said apparatus.
  • Fig. 3 is a perspective view of another loudspeaker according to the invention.
  • the loudspeaker assembly shown in Figs. 1 and 2 is in tended for high fidelity reproduction of the frequency range 25 to 20,000 c.p.s.
  • the casing 1 of the apparatus has the shape of a truncated cone, which shape has been found especially suitable.
  • a plate 24 closes the larger end thereof.
  • the loudspeaker may be placed on the floor (or alternatively mounted upside down 'on the ceiling) either in a corner or at a wall, with the axis of the body tilted, pointed out from the corner or the wall.
  • the casing 1 is provided with legs 2 which maintain the bottom surface 24, shown in Fig. 2, spaced from the floor.
  • the openings 3 and 4 located in the bottom surface 24 of the casing.
  • a loudspeaker mechanism 3' is mounted and the opening 4 is the port of a resonator cooperating with said mechanism and located in the lower part of the casing.
  • This unit of the loudspeaker assembly is mainly used for low frequencies up to 200 or 500 c.p.s. Higher frequencies are reproduced by a high frequency unit comprising a loudspeaker mechanism 5 mounted in the top of the casing 1. At frequencies where the sideward radiation of this loudspeaker mechanism 5 ceases, a second high frequency unit comprising a plurality of small loudspeaker mechanisms 6, '7, S and 9 take over the function.
  • the tilted axis of the casing provides the desired horizontal displacement of the low and high frequency units with respect to each other.
  • FIG. 3 Another embodiment of the inventon, using only one loudspeaker mechanism for the whole frequency range reproduced, is shown in Fig. 3.
  • the main body of the apparatus consists of a cylindrical casing 10, the axis of which is arranged in vertical position.
  • the casing 10 is provided with a coverll and a bottom wall 12.
  • a sound emitting surface or opening 13 in the cover emits as well high frequencies as medium and low frequencies, i.e. the whole frequency range.
  • Above said opening 13 of the apparatus is provided a reflector 14, coaxal with the opening 13.
  • the reflector which is connected with the casing 10 by means of rods, 15, is adapted to reflect high frequencies in horizontal directions.
  • Low frequencies are emitted through an opening 16 communicating with the casing 10 by means of a tube 17 forming part of an acoustic rmonator for said low frequencies.
  • the tube 17 serves as a carrying arm for the casing 10 and is provided with mounting means so that the whole apparatus can be mounted on a wall 18.
  • the apparatus can be mounted in any other way, e.g. on a tripod, but it is significant that the distances between the wall or the walls of the room and the opening 16 and the reflector 14 are maintained at the same proportions as shown in Fig. 3. V
  • a consequence of the invention is that it enables the adjacent reflecting surfaces of the listening-room to exert a predictable effect upon the transmission characteristics that can be considered when designing the sound reproducing apparatus.
  • the sound that arrives at the listener from the loudspeaker and those sunfaces of the room that are adjacent to the loudspeaker can be made in close replica of the input signal.
  • the fact that the loudspeaker radiates close to adjacent boundary surfaces of the listening-room causes the reflected sound from those surfaces of the room to be added in phase to the direct sound to provide an increased efficiency of low frequency transmission independent of the frequency variations within the low frequency range.
  • a loudspeaker cabinet comprising a substantially frusto-conical casing having a plate closing the larger end thereof, said plate having a loudspeaker opening and a resonance port therein, the smaller end of said casing providing an opening for the reception of a loudspeaker, said casing having at least one loudspeaker opening in the side thereof adjacent its smaller end, and supporting legs attached to the larger end thereof for supporting said casing at a desired location on a floor.
  • a loudspeaker cabinet as claimed in claim 1 having three legs, at least one leg being longer than another for supporting said casing in a tilted position whereby when said casing is located in the corner of a room and tilted away from said corner, said side opening can be spaced from a wall of said corner by a greater distance than the loudspeaker opening in said plate.
  • a loudspeaker cabinet as claimed in claim 1 having four openings in the side thereof adjacent its smaller end, said openings being spaced substantially equidistantly from each other around the 360 of the periphery of said casing side so as to accommodate a plurality of loud speakers facing in different directions.
  • a loudspeaker cabinet as claimed in claim 1 in which said opening in said smaller end is larger than said side opening so as to accommodate a loudspeaker of greater size than that accommodated in said side opening.
  • a loudspeaker cabinet comprising a substantially frusto-conical casing having a plate closing the larger end thereof, said plate having a loudspeaker opening and a resonance port therein, the smaller end of said casing providing an opening for the reception of a loudspeaker, said casing having several loudspeaker openings in the side thereof adjacent its smaller end, said openings facing in different directions, and three supporting legs attached to the larger end thereof which at least one leg is longer than another for supporting said casing in a tilted position at a desired location on a floor, whereby whensaid casing is located in the corner of a room and tilted away from said corner, the sound emanating from at least two of said side openings will be directed toward those two walls of the room, the intersection of which form said corner.
  • a loudspeaker cabinet comprising a substantially tubular casing having a plate closing one end thereof, said plate having a loudspeaker opening and a resonance port therein, the opposite end of said casing providing an opening for the reception of a loudspeaker, said casing having at least one loudspeaker opening in the side thereof adjacent said opposite end, and supporting legs attached to said casing adjacent said first mentioned end thereof for supporting said casing at a desired location on a floor.
  • a loudspeaker assembly for use in an enclosure having at least one substantially vertical wall and a floor, said assembly including at least two units having high and low frequency ranges respectively, the centers of radiation of said units, respectively, being displaced vertically and horizontally with respect to each other whereby said low frequency range unit may be placed closer to the floor and wall than said high frequency range unit.
  • a loudspeaker assembly as claimed in claim 7 in which the extent of said horizontal displacement of said units is substantial with respect to the distance between said low frequency range unit and said vertical Wall when said low frequency range unit is located sufliciently close to said vertical wall that the reflected sound pressure waves from said vertical wall will be added in phase or near in phase to the direct sound pressure waves from said low frequency range unit, whereby the center of radiation of said high frequency range unit may be spaced from said vertical wall by a distance which exceeds 1.6 times the distance between said vertical wall and the center of radiation of said low frequency range unit.
  • a loudspeaker assembly as claimed in claim 7 in which the radiation from said high frequency range unit is sufliciently omnidirectional as to cause a substantial portion of the high frequency radiation to be transmitted into said enclosure by reflection from said vertical wall when said high frequency range unit is located near said vertical wall, whereby said transmission by reflection will occur in a variety of directions.
  • a loudspeaker assembly as claimed in claim 7 which includes two units having high frequency ranges, one of said units comprising a loudspeaker mechanism which exhibits sideward radiation, and the other of said units comprising a plurality of smaller loudspeaker mechanisms which are oriented in different directions.
  • a loudspeaker assembly as claimed in claim 7 in which said high frequency range unit comprises a plurality of loudspeaker mechanisms oriented in dilferent directions so that a substantial portion of the high frequency radiation will be transmitted into said enclosure by reflection from said vertical wall when said high frequency range unit is located near said vertical wall.

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  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
US458650A 1953-10-02 1954-09-27 Loudspeaker apparatus Expired - Lifetime US2979149A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE788934X 1953-10-02

Publications (1)

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US2979149A true US2979149A (en) 1961-04-11

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ID=20336876

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Application Number Title Priority Date Filing Date
US458650A Expired - Lifetime US2979149A (en) 1953-10-02 1954-09-27 Loudspeaker apparatus

Country Status (4)

Country Link
US (1) US2979149A (fr)
FR (1) FR1118760A (fr)
GB (1) GB788934A (fr)
NL (2) NL191082B (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3360072A (en) * 1962-10-12 1967-12-26 Carlsson Stig Sound reproducing apparatus
US4006311A (en) * 1973-08-24 1977-02-01 Stig Carlsson Stereophonic sound reproducing apparatus
US20110019862A1 (en) * 2009-06-26 2011-01-27 DEI - Polk Audio, Inc. Ceiling-mounted loudspeaker enclosure
US8066095B1 (en) * 2009-09-24 2011-11-29 Nicholas Sheppard Bromer Transverse waveguide
US8867749B2 (en) 2011-04-18 2014-10-21 Paul Blair McGowan Acoustic spatial projector

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2823157B2 (ja) * 1986-04-01 1998-11-11 キヤノン株式会社 オーデイオ出力システム
GB2230408A (en) * 1989-03-17 1990-10-17 Dimitris Lioupis Loudspeakers

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2065367A (en) * 1935-12-31 1936-12-22 Robert B Evans Sound diffusing apparatus
US2143175A (en) * 1937-10-23 1939-01-10 Samuel A Waite Sound reproducing system
US2179840A (en) * 1938-05-03 1939-11-14 Frida Bucky Loudspeaker arrangement
US2206427A (en) * 1937-03-31 1940-07-02 Rca Corp Sound reproducing apparatus
US2373692A (en) * 1942-10-03 1945-04-17 Ray L Smith Loud-speaker
FR913655A (fr) * 1945-03-22 1946-09-17 Perfectionnements aux appareils reproducteurs électriques de sons tels que radio-récepteurs et phonographes
FR54541E (fr) * 1946-05-09 1950-05-04 Perfectionnements aux appareils reproducteurs électriques de sons tels que radio-récepteurs et phonographes
GB641668A (en) * 1946-09-20 1950-08-16 Standard Telephones Cables Ltd Sound reproduction devices
US2610694A (en) * 1944-05-30 1952-09-16 Hartford Nat Bank & Trust Co Stereophonic reproduction apparatus
US2694462A (en) * 1951-09-19 1954-11-16 Robbins Frank Acoustic system for loud-speakers
US2701025A (en) * 1952-02-05 1955-02-01 George H Kuhl High fidelity sound system
US2722990A (en) * 1949-11-08 1955-11-08 Decca Record Co Ltd Loudspeaker assemblies
US2824617A (en) * 1952-09-15 1958-02-25 Philips Corp Sound reproducing device

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2065367A (en) * 1935-12-31 1936-12-22 Robert B Evans Sound diffusing apparatus
US2206427A (en) * 1937-03-31 1940-07-02 Rca Corp Sound reproducing apparatus
US2143175A (en) * 1937-10-23 1939-01-10 Samuel A Waite Sound reproducing system
US2179840A (en) * 1938-05-03 1939-11-14 Frida Bucky Loudspeaker arrangement
US2373692A (en) * 1942-10-03 1945-04-17 Ray L Smith Loud-speaker
US2610694A (en) * 1944-05-30 1952-09-16 Hartford Nat Bank & Trust Co Stereophonic reproduction apparatus
FR913655A (fr) * 1945-03-22 1946-09-17 Perfectionnements aux appareils reproducteurs électriques de sons tels que radio-récepteurs et phonographes
FR54541E (fr) * 1946-05-09 1950-05-04 Perfectionnements aux appareils reproducteurs électriques de sons tels que radio-récepteurs et phonographes
GB641668A (en) * 1946-09-20 1950-08-16 Standard Telephones Cables Ltd Sound reproduction devices
US2722990A (en) * 1949-11-08 1955-11-08 Decca Record Co Ltd Loudspeaker assemblies
US2694462A (en) * 1951-09-19 1954-11-16 Robbins Frank Acoustic system for loud-speakers
US2701025A (en) * 1952-02-05 1955-02-01 George H Kuhl High fidelity sound system
US2824617A (en) * 1952-09-15 1958-02-25 Philips Corp Sound reproducing device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3360072A (en) * 1962-10-12 1967-12-26 Carlsson Stig Sound reproducing apparatus
US4006311A (en) * 1973-08-24 1977-02-01 Stig Carlsson Stereophonic sound reproducing apparatus
US20110019862A1 (en) * 2009-06-26 2011-01-27 DEI - Polk Audio, Inc. Ceiling-mounted loudspeaker enclosure
US8634586B2 (en) * 2009-06-26 2014-01-21 Polk Audio, Inc. Ceiling-mounted loudspeaker enclosure
US8066095B1 (en) * 2009-09-24 2011-11-29 Nicholas Sheppard Bromer Transverse waveguide
US8867749B2 (en) 2011-04-18 2014-10-21 Paul Blair McGowan Acoustic spatial projector

Also Published As

Publication number Publication date
FR1118760A (fr) 1956-06-11
NL97567C (fr)
NL191082B (nl)
GB788934A (en) 1958-01-08

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