US2034014A - High-fidelity sound reproducing apparatus and method of improving the fidelity thereof - Google Patents

High-fidelity sound reproducing apparatus and method of improving the fidelity thereof Download PDF

Info

Publication number
US2034014A
US2034014A US14600A US1460035A US2034014A US 2034014 A US2034014 A US 2034014A US 14600 A US14600 A US 14600A US 1460035 A US1460035 A US 1460035A US 2034014 A US2034014 A US 2034014A
Authority
US
United States
Prior art keywords
sound
cavity
fidelity
vertex
casing
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
Application number
US14600A
Other languages
English (en)
Inventor
Harold A Wheeler
Vernon E Whitman
Nelson P Case
William O Swinyard
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems Aerospace Inc
Original Assignee
Hazeltine Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL51541D priority Critical patent/NL51541C/xx
Application filed by Hazeltine Corp filed Critical Hazeltine Corp
Priority to US14600A priority patent/US2034014A/en
Application granted granted Critical
Publication of US2034014A publication Critical patent/US2034014A/en
Priority to FR804389D priority patent/FR804389A/fr
Priority to DE1936H0147183 priority patent/DE691238C/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
    • H04R1/36—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means by using a single aperture of dimensions not greater than the shortest operating wavelength
    • 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

  • a second important problem is that of the ef-- fectiveness of the device and the closely related problem of the distribution of the sound waves in their projection from the device to the audience,
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, such as a corner of a room.
  • a large-diaphragm type of sound-reproducing device disposed to discharge, preferably vertically, into the sound cavity at a point displaced from the vertex.
  • sound cavity includes means for directing or defleeting the sound waves generated by the device outwardly from the vertex with a substantially uniform angular distribution and a proper vertical distribution, as determined by the physical relationship of the sound-reproducing device to an audience.
  • a high-fidelity sound substantially to the corner of a room so that the walls and floor or ceiling constitute effectively a continuation of the walls of the sound cavity.
  • a partition separates the cavity from the rest of'the casing and a large-diaphragm type sound-reproducing device is disposed in an opening in the partition to discharge vertically into the cavity.
  • a conical deflector is positioned between the sound-reproducing device and the opening of the sound cavity and is effective to direct outwardly from the vertex. the sound waves generated by the device.
  • One or more additional segmental coni- Thev cal deflectors and a plurality of vertical fins radi- "ating from a point of the interior of the cavity substantially on the axis of the sound-reproducin'g device effect a uniform angular distribution and a proper vertical distribution of the sound waves generated by the device into the room-0r auditorium in which the apparatus is placed.
  • the remaining portion of the casing comprises a rigid, substantially anti-resonant structure lined with a sound-absorbent material.
  • a large mass of sound-absorbent material is disposedln the end of the casing opposite the sound cavity in the form of a pyramid having as its base the end of the casing and having its vertex in the corner including the vertex of the sound reproduction ofapparatus embodying our invention the electrical transmissionnetwork supplying energy to the sound-reproducing device is compensated for resultant or residual lack of unir formity in the frequency-response characteristic of the apparatus by associating therewith.
  • Such a 'network may comprise oneor more series resonant circuits connected in parallel and having natural frequencies orresponding tothe peaks of the frequency-respouse characteristic of the device and one or more parallel resonant circuits having natural frequencies corresponding to the dips of the frequency-response characteristic.
  • FIG. 1 is a view in perspective of "a sound-reproducing apparatus" constructed in accordance with ourinvention
  • Fig. 2 is a longitudinal section of the apparatus ofFig. 1 taken along the lines 2-.-2 of 'Fig. 4
  • Figs, 3 and 4 are cross-sectionalviews of the ap paratus of Fig. 1 taken along thelines 3-8 and. 4-4, respectively, of Fig. 2
  • Fig Sirepresents certain operating characteristics of the apparatus of Figs. 1-4 inclusive,- and certain corrections applied thereto in accordance with our invention
  • FIG. 6 is a'schematic circuit diagram of a complete radio broadcast receiver, to which the sopndereproducing-apparatus of our inven tion may suitably be-applied, including a network for compensating for any residual lack of uniformity in the frequency-response characteristic of our improved sound-reproducing apparatus.
  • a sound-reproducing apparatus embodying our. inv vention comprising a casingor housing l terminating at its lower end in a'sound cavity I I which is separated from the upper portion. of the easing by a partition I2.
  • An opening Ila is pro-' vided in the partition in which or over which is mounted a sound-reproducing device or element I 3,0! the large-diaphragm type.
  • large-diaphragm type sound-reproducing de me is meant a device having a relatively large vibrating diaphragm, usually conical, which, because of its size, produces directly sound waves of sumclent intensity for usual purposes.
  • Such a device is to-be distinguished from the small-dia- 1 phragm type of sound-reproducing device which is useful only in connection with a sound-amplifying device, such as a horn.
  • the sound cavity II is'open on two sides while its two rearsides terminate in the comer Il a, shaped to conform corner of the casing I0, as indicated at, Illa.
  • a conical deflector I the axis of which lies in the vertical through the vertex of the sound cavity II and the base of which is'substantially 'coextensive with the base of the sound cavity II.
  • the front angle of the conical deflector I 5 is not critical but is determined, among other considerations, by the height of the partition I:
  • the base of the should be such as todirect the sound waves gen-- sound waves.
  • the deflector I5 serves principally to reflectthe downwardly projected sound waves outwardly into the room.
  • the fins I1 and I8 may terminate in a fin 19 extending to the rear comer of the sound cavity I I.
  • the conical deflectors I5 and I6 and the verticalflns I I, I 8 and I9 must be of suflicient rigidity to prevent substantial mechanical vibration in the audio-frequency range, and to'thise'nd they may comprise sheets of moderately heavy gauge metal, welded, soldered, or otherwise fabricated into a unitary structure.
  • the upper portion of the casing lfl above the partition I2 constitutes av closed sound-absorb ing chamber to prevent'interference'of the sound waves generated at the rear of the diaphragm of the device I3 with the main sound waves which it is desired to utilize.
  • This portion of the casing is also preferablyconstructed of relatively heavy.
  • a sound-absorbing sheet material 20 which may be of any suitable type, as, for example, a fibrous sheetmaterial commercially available as Acousti-Celotex.
  • a screen or other sonnd-pervious sheet-or strip 2I divides off from the upper portion of the 09.5-- ing a pyramidal cavity the baseof which constitutes the top of theca'sing III and the vertex of which lies at the rear corner of the casing; that is, in a vertical through the vertex of the sound cavity I I..
  • This chamber 22 is filled with a sound-' absorbent material such as rock wool or slag wool,
  • a fabric covering may be provided for the screen 2
  • the conical configuration of the deflector I5 tends to produce substantially uniform angular distribution of the
  • the inclination of the deflector I5 should preferably be suchas to deflect the sound waves upwardly at such anangle as to reach the head of a listener in substantially the center of a-room in which the apparatus is to be utilized; This result maybeseto provide a more equal or uniform angular distribution of the sound waves, the deflector I5 being effective also to increase the uniformity of the vertical distribution of the sound waves. as they leave the sound cavity I I. It has been found that the fins l1 and I8 and deflector l5 are particularly effective over a range of audio frequency of from 600 to l200cycles.
  • the portion of the casing 10 above the sound cavity I! is effective to absorb sound waves generated by the rear of the diaphragm of the device l3, and this absorption should be effected without mechanical vibration of any of the casing structure.
  • Such mechanical vibration is sub stantially avoided, as described above, by utilizing relatively rigid walls, with or without bracing, and by lining the walls with a sound-absorbent material.
  • the resonant properties of the casing avoided by this means should be distinguished; however, from the resonant properties of the enclosed body of air. Resonance of the body of air is minimized by the pyramidal mass of sound-absorbent material 22, which renders the portion of the casing above the baiiie I!
  • This beveling of the front corner of the casing substantially eliminates any parallel surfaces in this portion of the casing and thereby substantially eliminates the resonance effects or standing waves; facilitates high-angle reflection and aids in the'better utilization of the corner space of the room.
  • the vertical opening of the sound cavlty- H is preferably of the order of magnitude of the diameter of the diaphragm of the device l3.
  • the total height of the housing It is not critical but is preferably atleast 5 or 6 times the diameter of the diaphragm and should provide sufilcient volume to build up the low notes generated by the device.
  • the diaphragm of the-device I3 is preferably parallel to the floor, although it maybe inclined slightlythereto, the inclination of the. deflectors l5 and i6 being correspondingly modified.
  • casing l0 and'particularly the soun cavity H thereof, has been illustrated as conforming substantially to a righttrihedral angle such as the corner of a room, it will be apparent 1 'that it may conform to any polyhedral angle, or, in general, to any conical shape, in case it is to" verted with the sound cavity immediately adjacent the ceiling and the same principles of oper ation will govern the performance of the apparatus.
  • curve A of Fig. 5 represents a correction curve which, if applied to the apparatus whose characteristic is represented by the curve A, would produce absolutely uniform frequency response.
  • the curve B is, obviously, the inverse of the curve A.
  • Curve C in this same figure, represents a correction curve obtainable by a frequency-selective network, to
  • curve D represents the frequency-response characteristic of a complete system embodying our invention.
  • the average of the curve I) has been moved upwardly from'the other curves to avoid confusion and since it is relative, and not abso-' lute, values of the response which are important. It is seen that the curve D does not depart from its average value more than about i3 decibels.
  • FIG. 6 of the drawings is a schematic diagram of a complete radio broadcast receiver modified in accordance with our invention.
  • This system includes an input circuit 30 for connection between an antenna and ground, a radio-frequency amplifier 31, an oscillator-modulator 32, an intermediate-frequency amplifier 33, and a detector 34, all coupled in-cascade.
  • the output of the detector 34 is fed to an audio-frequency amplifier including the vacuum tubes 35 and 36 connected in any conventional manner, the circuits of which form 'no part of our present invention.
  • the audio-frequency amplifier is, in turn, coupled to a pushpull power amplifier including vacuum tubes 31 and 38 and associated circuit elements, also connected in a conventional manner, which, in turn, are connected to sound-reproducing device 39, which is of the type illustrated in, and described in connection with Figs. 1-4 inclusive.
  • a frequency-selective network 40 is included in the cathode circuit of the vacuum tube 35.
  • This network comprises a parallel resonant circuit consisting of an inductance 4
  • a blocking condenser 46 Connected in parallel with the two serially connected parallel resonant circuits just described, through a blocking condenser 46, are the pairs of series resonant circuits comprising inductances 41,49, 5i and 53 and condensers 48, 50, 52 and 54, respectively. Further, there is connected in parallel with the voice coil or the sound-reproducing device 39 a frequency-selective network 55, represented in dotted outline, comprising series resonant in-. ductance 56 and'condenser 51.
  • the frequency-selective networks may have the following values:
  • the parallel resonant circuit Al, 42 produces the dip in curve C at'2800 cycles; the parallel resonant circuit 4 5, 45 produces the dip at 150 cycles; the series resonant circuit 56, 51 in the circuit of the soundreproducing device produces a desired dip at 10,000 cycles.
  • the series resonant circuit 41, 48 produces the peakat 55 I cycles; the circuit 49, produces the peak at 250 cycles; the circuit 5
  • the circuit constants for procuring the correction curve C may be determined empirically or computed in any of several well known manners. Fromthe foregoing'description it is apparent that, in accordance with our invention,
  • apparatus for, compensating for any residual non-uniformity in the frequency-response characteristic within any desired limits, whereby the deviation of the frequency-response curve from its average value may be maintained within any assigned error, by proper design of the frequencyselective network.
  • a high-fidelity sound-reproducing apparatus comprising a'casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a cornerof a room, a large-diaphragm type sound-reproducing device disposed to radiate sound waves approximately vertically into said cavity, and means for directing outwardly and distributing uniformly the sound waves radiated by said device.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room, a largediaphragm type sound-reproducing device disposed to radiate sound wavesapproximately vertically into said cavity, and aconical deflector positioned below said device and effective to direct and distribute sound waves radiated by said device outwardly from said vertex.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, asa corner of a. room, a largediaphragm type sound-reproducingdevice disposed to radiate sound waves approximately vertically into said cavity, and rigid conical deflecting means positioned below said device and efiective to direct and distribute sound waves radiated by said device outwardly from said vertex.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room, a largediaphragm type sound-reproducing device disposed to radiate sound waves approximately vertically into said cavity, and a rigid conical deflector having its axis lying in a vertical intersecting said vertex and substantially coextensive with said cavity, said deflector being efiective to direct and distribute outwardly from said vertex the sound waves radiated by said device.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a'sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room, a largediaphragm type sound-reproducing device disposed to radiate sound waves approximately vertically into said cavity, and a rigid conical de-y fiector having a vertical 'angle of the order of and disposed with its axis lying'in a vertical intersecting said vertex, said deflector extending substantially to the periphery of the bottom of said cavity and being efiective to direct and distribute outwardly from said vertex the sound waves radiated by said device.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shapedto conform substantially to the vertex of a trihedral angle, as a. corner of a room, a largediaphragm type sound-reproducing device disposed to radiate sound waves approximately vertically into said cavity,- and a rigid conical defiector having a'vertical angle of from 110 to and disposed with its axis lying in a vertical' intersecting said vertex, said deflectorbeing efl'ective to direct and distribute outwardly from said. vertex the sound waves radiated by said device.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner 01' a room, a largeinto said cavity," the vertical depth of said cavity diaphragm type sound-reproducing device disposed to radiate sound waves approximately vertically into said cavity, a conical deflector positioned below said device and effective to direct outwardly from said vertex sound waves radiated by said device, and additional means for effecting uniform angular distribution of said deflected waves.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavityshaped to conform substantially to the vertex of a trihedral angle, as a comer of a room, a large-diaphragm type sound-reproducing device disposed to radiate sound waves approximately vertically into said cavity, a conical deflector positioned be-' low said device and effective to direct outwardly from said vertex sound waves radiated by said device, and a plurality of fins radiating from the interior of said cavity effecting-a uniform angular distribution of said-deflected waves.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room, a largediaphragm type sound-reproducing device dis-.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room, a large- Y diaphragm type sound-reproducing device discluding a segmental conical deflector parallel to said first-named deflector and a plurality of vertical fins, said segmental deflector and said fins radiating substantially from the axis of said diaphragm to the periphery of said cavity.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room, a horisontal partition defining the upper boundary .of said cavity, a large-diaphragm type sound-reproducing device disposed in an opening in said partition and radiating sound waves vertically into said cavity, and means for directing outwardly and distributing uniformly the sound waves radiated by said device.
  • a high-fidelity sound-reproducing apparatus comprising a casing including a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room, a horizontal partition defining the upper boundary of said cavity, a large-diaphragm type sound-reproducing device disposed in an opening in said 7 partition and radiating sound waves vertically being of the order of the diameter of said diaphragm, and means'for directing outwardly and distributing uniformly the sound waves radiated by said device.
  • a high-fidelity sound-reproducing apparatus comprising a casing terminating in a sound cavity shaped to conform substantially to the vertex'of a trihedral angle, as a corner of a room, a partition separating said cavity from the rest of said casing, a large-diaphragm type sound-reproducing device disposed in an opening in said partition to radiate sound waves substantially, vertically into said cavity, means for directing the sound waves radiated by said device outwardly from said vertex, and means for rendering the casing above said partition substantially non resonant.
  • a h gh-fidelity soimd-reproducing apparatus comprising a casing terminating in a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as 'a corner of a room, a partition separating said cavity from the rest of.
  • a large-diaphragm type soundreproducing device disposed in an opening in said partition to radiate sound waves substantially vertically into said cavity, means for directing the sound waves generated by said device outwardlyfrom said vertex, and means for rendering the casing above said partition substantially non-resonant, comprising a lining of sound-ab- .sorbent material and a mass of sound-absorbent material at the opposite end of said casing from said cavity and formed with a surface inclined to said partition.
  • a high-fidelity sound-reproducing apparatus comprising a casing terminating in a sound cavity shaped to conform substantially to the vertex of a trihedral angle, as a corner of a room,
  • a partition separating said cavity from the rest of said casing, a large-diaphragm type sound-reproducing device disposed in an opening in said partition to radiate sound waves substantially vertically into said cavity, means for directing the sound waves radiated by said device outwardly from said vertex, and means for rendering the casing above said partition substantially anti-resonant, comprising a lining of sound-absorbent material and a mass of sound-absorbent material disposed to form a pyramid having as its base the end of said casing opposite said cavity and having its vertex at the corner of said casing including the vertex of said cavity.

Landscapes

  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Building Environments (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
US14600A 1935-04-04 1935-04-04 High-fidelity sound reproducing apparatus and method of improving the fidelity thereof Expired - Lifetime US2034014A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL51541D NL51541C (xx) 1935-04-04
US14600A US2034014A (en) 1935-04-04 1935-04-04 High-fidelity sound reproducing apparatus and method of improving the fidelity thereof
FR804389D FR804389A (fr) 1935-04-04 1936-04-02 Appareil de reproduction de sons
DE1936H0147183 DE691238C (de) 1935-04-04 1936-04-04 Lautsprechergeraet mit einem der Ecke eines Zimmers angepassten Gehaeuse

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US14600A US2034014A (en) 1935-04-04 1935-04-04 High-fidelity sound reproducing apparatus and method of improving the fidelity thereof

Publications (1)

Publication Number Publication Date
US2034014A true US2034014A (en) 1936-03-17

Family

ID=21766445

Family Applications (1)

Application Number Title Priority Date Filing Date
US14600A Expired - Lifetime US2034014A (en) 1935-04-04 1935-04-04 High-fidelity sound reproducing apparatus and method of improving the fidelity thereof

Country Status (4)

Country Link
US (1) US2034014A (xx)
DE (1) DE691238C (xx)
FR (1) FR804389A (xx)
NL (1) NL51541C (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2623606A (en) * 1948-06-30 1952-12-30 Corke Alfred James Sound reproduction apparatus
US2858899A (en) * 1956-07-03 1958-11-04 Lopez-Henriquez Miguel High fidelity speaker enclosure system
US2975852A (en) * 1954-01-05 1961-03-21 Chave Donald Maynard Loudspeakers
US4146111A (en) * 1976-01-19 1979-03-27 Trio Kabushiki Kaisha Speaker system
US4313521A (en) * 1980-06-16 1982-02-02 Rodden M Raymond Speaker housing
USD769215S1 (en) * 2014-07-15 2016-10-18 Funktion One Research Loudspeaker
USD780159S1 (en) * 2014-07-15 2017-02-28 Funktion One Research Loudspeaker
USD780158S1 (en) * 2014-07-15 2017-02-28 Funktion One Research Loudspeaker

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4307655C2 (de) * 1993-03-11 1996-11-07 Automation Dr Meggl Gmbh Lautsprecheranordnung

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2623606A (en) * 1948-06-30 1952-12-30 Corke Alfred James Sound reproduction apparatus
US2975852A (en) * 1954-01-05 1961-03-21 Chave Donald Maynard Loudspeakers
US2858899A (en) * 1956-07-03 1958-11-04 Lopez-Henriquez Miguel High fidelity speaker enclosure system
US4146111A (en) * 1976-01-19 1979-03-27 Trio Kabushiki Kaisha Speaker system
US4313521A (en) * 1980-06-16 1982-02-02 Rodden M Raymond Speaker housing
USD769215S1 (en) * 2014-07-15 2016-10-18 Funktion One Research Loudspeaker
USD780159S1 (en) * 2014-07-15 2017-02-28 Funktion One Research Loudspeaker
USD780158S1 (en) * 2014-07-15 2017-02-28 Funktion One Research Loudspeaker

Also Published As

Publication number Publication date
DE691238C (de) 1940-05-20
FR804389A (fr) 1936-10-22
NL51541C (xx)

Similar Documents

Publication Publication Date Title
US2143175A (en) Sound reproducing system
US9883283B2 (en) Acoustic deflector for omni-directional speaker system
US2224919A (en) Loud-speaker
US1969704A (en) Acoustic device
US2293181A (en) Sound absorbing apparatus
US10034081B2 (en) Acoustic filter for omnidirectional loudspeaker
US2034014A (en) High-fidelity sound reproducing apparatus and method of improving the fidelity thereof
US2975852A (en) Loudspeakers
US6026928A (en) Apparatus and method for reduced distortion loudspeakers
US2031500A (en) Sound reproducing system
US4593784A (en) Loudspeaker enclosure
US1965405A (en) Acoustic device
US2969848A (en) Bass speaker enclosure
US2816619A (en) Acoustic transducers
US2979150A (en) High fidelity loud speaker cabinet
US1901388A (en) Method and apparatus for eliminating the effect of cabinet resonance
US2646851A (en) Loud-speaker baffle with elongated aperture for the egress of sound
US2856467A (en) Compound diffraction horn
US1823512A (en) Loud speaker
US2845135A (en) Auxiliary wave propagating and directing attachment for loudspeaker diaphragms
US3089562A (en) Loudspeaker baffle assembly
US2297972A (en) Sound reproducing device
US1876831A (en) Sound reproducer
US2811215A (en) Sound reproducing apparatus
US2071828A (en) Loudspeaker, sound reproducing instrument, and the like