US2135610A - Horn - Google Patents

Horn Download PDF

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Publication number
US2135610A
US2135610A US110646A US11064636A US2135610A US 2135610 A US2135610 A US 2135610A US 110646 A US110646 A US 110646A US 11064636 A US11064636 A US 11064636A US 2135610 A US2135610 A US 2135610A
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US
United States
Prior art keywords
horn
mouth
walls
auditorium
sound
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
US110646A
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English (en)
Inventor
Edward C Wente
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.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
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 BE424560D priority Critical patent/BE424560A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US110646A priority patent/US2135610A/en
Application granted granted Critical
Publication of US2135610A publication Critical patent/US2135610A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H04R1/345—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 for loudspeakers

Definitions

  • This invention relates to the reproduction of sound and particularly to horns for loud-speaking receivers in public address systems.
  • the receiver In systems of this type it is well understood that for a realistic reproduction the receiver should be located so that the sounds heard appear to come from the direction of theoriginal source. This requires that the receiver be mounted near the sound source and it is common practice to place it above the speaker's stand. It is also well known that to enable the system to be operated at sufficient gain to. give adequate coverage of the reproducing area without singing" the pick-up microphone must be located within the acoustic shadow of the receiver.
  • Such a room is in eflect a long, narrow channel with its lower surface highly absorbing due to the presence of the audience so that sound projected from the front toward the rear is highly attenuated and the attenuation increases with frequency, a condition which is particularly unfavorable to the transmission of intelligible speech.
  • the-gain cannot be greatly increased to compensate for the attenuation since, because of the low ceiling height, some coupling between the microphone and the receiver cannot be avoided and when the gain is increased the system soon reaches the "singing condition.
  • the object'of'thls invention is a loud-speaking receiver horn which will distribute the sound energy more evenly over all parts of such auditoriums and which will preserve the illusion in all parts of the room of hearing the speaker's unaided voice.
  • the horn has an. angle of projection limited in both lateral and vertical directions as required by the configuration of the area to be covered but within this angle it combines the uniform distribution of energy obtainable with a conical horn with the high conversion eillciency 01 the exponential type; It diverges from a throat portion which is small to a mouth which is large as compared withthe wave-lengths of the frequencies within the range to be projected.
  • the four boundary walls are all plane surfaces to give the spherical wave front of a conical type l horn and the mouth portion is subdivided by vertical partition walls which are contoured in such a way that each longitudinal horn section varies in cross-section exponentially.
  • each section is made small enough so that the directive beam effect at the higher frequencies is not excessive.
  • the waves are projectedat high efficiency and uniform quality over the solid angle defined by the bounding walls withoutsubstantial diffraction at the horn mouth.
  • a further feature of this invention is a horn with one bounding wall normal to the mouth opening, the horn being mounted with this wall against the ceiling of the auditorium. This is the equivalent of dividing a horn along its axis of symmetry and using only one-half of the horn structure. Since there is no flow of energy across the axis of symmetry, this division. does not affect the wave front and 39 from the standpoint of difl'raction in the vertical plane it gives the effect of a horn of twice its actual vertical dimension.
  • Fig. 1 is a side view of a horn according to the invention
  • Fig. 21 s a horizontal sectional view of the horn
  • Fig. 3 is a front view of the'horn
  • Figs. 4 and 5 are plan and sectional views of an auditorium showing the projection ngle of 40 the horn.
  • the horn shown has a throat portion II and a mouth portion 12, of which the, upper bounding walls I; and H are coplanar and normal to the plane of the mouth l5 so that the horn may be mounted directly against the ceiling of an auditorium.
  • the receiver unit 16 is connected by means of suitably curved and tapered tube I I to the throat portion II the lower wall l8 of which slopes downwardly at angle of 25 degrees. In the vertical plane the sound waves. therefore, spread out with circular wave fronts as in a conical horn.
  • the vertical walls I! and 20 (Fig.2) of the throat may be substantially plane parallel since most 01 u the flare necessary for an exponential variation is obtained by the divergence of the lower wall 18.
  • continue in line with the corresponding walls of the throat but the vertical walls diverge in planes forming an angle of degrees.
  • the mouth portion is bounded by four plane walls and if not subdivided would therefore have substantially the transmission characteristics of a conical horn (that is to say, the sound waves would emerge from the mouth with spherical wave fronts and would proceed toward the rear of the auditorium without substantial diffraction but the conversion efiiciency of such a horn is-relatively low as compared with an exponential horn).
  • partitions 22 are disposedvertically in the mouth portion and divide it into three sections 23, 24 and 25 of the same crosssectional area at equal distances from the horn throat.
  • These partitions may be composed of balsa wood or other non-resonant material and are contoured so that each section has an exponential taper.
  • the sound waves entering the mouth portion are intercepted by the partitions and pass along the three sections 23, 24 and 25 substantially as sections of a spherical wave front which merge into a spherical wave at the mouth opening and continue out without material increase in divergence through diffraction since the combined .wave front at the horn mouth is large as compared with the wave-length down to quite low frequencies.
  • a horn for loud-speaking receivers bounded on all sides throughout its length by plane surfaces diverging from a throat portion, which is small compared to the wave-lengths of the frequencies to be projected, to a mouth which is large compared to said wave-lengths, said mouth having contoured partition walls dividing it into a plurality of sound passages each decreasing in cross-section exponentially throughout its length and extending back between the plane surfaces toward the throat of the horn to a point where the width of each passage is small as compared to said wave-lengths.
  • a horn according to claim 1 in which one of the bounding walls is normal to the mouth opening and is adapted to be mounted against the ceiling of an auditorium to increase the effective height of the mouth opening.

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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)
US110646A 1936-11-13 1936-11-13 Horn Expired - Lifetime US2135610A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE424560D BE424560A (en)) 1936-11-13
US110646A US2135610A (en) 1936-11-13 1936-11-13 Horn

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US110646A US2135610A (en) 1936-11-13 1936-11-13 Horn

Publications (1)

Publication Number Publication Date
US2135610A true US2135610A (en) 1938-11-08

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Family Applications (1)

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US110646A Expired - Lifetime US2135610A (en) 1936-11-13 1936-11-13 Horn

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BE (1) BE424560A (en))

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2458038A (en) * 1942-08-29 1949-01-04 Rca Corp Acoustical apparatus
US3852529A (en) * 1973-01-10 1974-12-03 Motorola Inc Acoustic horn
FR2553249A1 (fr) * 1983-10-05 1985-04-12 Jbl Inc Pavillon de haut-parleur couvrant une zone delimitee
US4776428A (en) * 1987-11-16 1988-10-11 Belisle Acoustique Inc. Sound projection system
US20040216948A1 (en) * 2003-02-21 2004-11-04 Meyer Sound Laboratories Incorporated Loudspeaker horn and method for controlling grating lobes in a line array of acoustic sources
GB2425436A (en) * 2005-04-21 2006-10-25 Martin Audio Ltd Loudspeaker horn with movable sound-dispersing vane
US7275621B1 (en) 2005-01-18 2007-10-02 Klipsch, Llc Skew horn for a loudspeaker
US20080128199A1 (en) * 2006-11-30 2008-06-05 B&C Speakers S.P.A. Acoustic waveguide and electroacoustic system incorporating same
JP2012242040A (ja) * 2011-05-23 2012-12-10 Rinnai Corp ガスコンロ
US8718310B2 (en) 2001-10-19 2014-05-06 Qsc Holdings, Inc. Multiple aperture speaker assembly
US8824717B2 (en) 2001-10-19 2014-09-02 Qsc Holdings, Inc. Multiple aperture diffraction device
US11151972B2 (en) * 2016-10-21 2021-10-19 Harman International Industries, Incorporated Acoustic component, acoustic apparatus and acoustic system

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2458038A (en) * 1942-08-29 1949-01-04 Rca Corp Acoustical apparatus
US3852529A (en) * 1973-01-10 1974-12-03 Motorola Inc Acoustic horn
FR2553249A1 (fr) * 1983-10-05 1985-04-12 Jbl Inc Pavillon de haut-parleur couvrant une zone delimitee
EP0140465A3 (en) * 1983-10-05 1986-03-19 Jbl Incorporated Defined-coverage loudspeaker horn
US4776428A (en) * 1987-11-16 1988-10-11 Belisle Acoustique Inc. Sound projection system
US8718310B2 (en) 2001-10-19 2014-05-06 Qsc Holdings, Inc. Multiple aperture speaker assembly
US9204212B2 (en) * 2001-10-19 2015-12-01 Qsc Holdings, Inc. Multiple aperture speaker assembly
US8824717B2 (en) 2001-10-19 2014-09-02 Qsc Holdings, Inc. Multiple aperture diffraction device
US20040216948A1 (en) * 2003-02-21 2004-11-04 Meyer Sound Laboratories Incorporated Loudspeaker horn and method for controlling grating lobes in a line array of acoustic sources
US7299893B2 (en) 2003-02-21 2007-11-27 Meyer Sound Laboratories, Incorporated Loudspeaker horn and method for controlling grating lobes in a line array of acoustic sources
US7275621B1 (en) 2005-01-18 2007-10-02 Klipsch, Llc Skew horn for a loudspeaker
US20090277713A1 (en) * 2005-04-21 2009-11-12 Ambrose Thopson Acoustic Loading Device for Loudspeakers
US8191674B2 (en) 2005-04-21 2012-06-05 Martin Audio Limited Acoustic loading device for loudspeakers
GB2425436B (en) * 2005-04-21 2007-06-06 Martin Audio Ltd Acoustic loading device for loudspeakers
GB2425436A (en) * 2005-04-21 2006-10-25 Martin Audio Ltd Loudspeaker horn with movable sound-dispersing vane
US20080128199A1 (en) * 2006-11-30 2008-06-05 B&C Speakers S.P.A. Acoustic waveguide and electroacoustic system incorporating same
JP2012242040A (ja) * 2011-05-23 2012-12-10 Rinnai Corp ガスコンロ
US11151972B2 (en) * 2016-10-21 2021-10-19 Harman International Industries, Incorporated Acoustic component, acoustic apparatus and acoustic system

Also Published As

Publication number Publication date
BE424560A (en))

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