US3360771A - Underwater horn loudspeaker - Google Patents
Underwater horn loudspeaker Download PDFInfo
- Publication number
- US3360771A US3360771A US457701A US45770165A US3360771A US 3360771 A US3360771 A US 3360771A US 457701 A US457701 A US 457701A US 45770165 A US45770165 A US 45770165A US 3360771 A US3360771 A US 3360771A
- Authority
- US
- United States
- Prior art keywords
- horn
- vibratory
- underwater
- sound
- transducer
- 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
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 238000006073 displacement reaction Methods 0.000 claims description 4
- 230000003534 oscillatory effect Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-PWCQTSIFSA-N Tritiated water Chemical compound [3H]O[3H] XLYOFNOQVPJJNP-PWCQTSIFSA-N 0.000 claims 1
- 239000000463 material Substances 0.000 description 9
- 230000005855 radiation Effects 0.000 description 8
- 239000004567 concrete Substances 0.000 description 6
- 230000006872 improvement Effects 0.000 description 5
- 230000004044 response Effects 0.000 description 4
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000003923 scrap metal Substances 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
- G10K11/025—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators horns for impedance matching
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/18—Methods or devices for transmitting, conducting or directing sound
- G10K11/26—Sound-focusing or directing, e.g. scanning
- G10K11/28—Sound-focusing or directing, e.g. scanning using reflection, e.g. parabolic reflectors
-
- 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
- Y10S181/00—Acoustics
- Y10S181/40—Wave coupling
- Y10S181/402—Liquid
Definitions
- UNDERWATER HORN LOUDSPEAKE R Filed May 21, 1965 I. 9 2.0 2. ⁇ FREQUENCY ⁇ N KC DB. vs. I MICROBAR AT 1 v0 United States Patent Ofiice 3,360,771 Patented Dec. 26, 1967 3,360,771 UNDERWATER HORN LOUDSPEAKER Frank Massa, Jr., Cohasset, Mass., assignor to Massa Division Dynamics Corporation of America, Hingham, Mass.
- the present invention is concerned generally with underwater loudspeakers and, more particularly, with an improved horn for increasing the efficiency of underwater sound generators. If a vibrating piston is to be used as an underwater sound source and its diameter is small compared to the wavelength of sound corresponding to the frequency of vibration, the acoustic loading on the piston is reduced with a resulting reduction in acoustic power radiation. In order to achieve full acoustic loading on a circular vibrating surface, its diameter should be at least equal to approximately /3 the wavelength of sound being radiated.
- the square root of the area of the vibrating surface should be approximately equal to /3 the wavelength of the radiated sound.
- the primary object of this invention is to improve the acoustic loading on the vibrating surface of an underwater sound generator whose surface dimensions are small compared to the wavelength of the radiated sound.
- Another object of this invention is to provide a horn structure for use underwater that will serve as an effective acoustic transformer for increasing the acoustic loading on a small vibrating surface, whereby the acoustic power radiated from the vibrating surface is increased.
- a still further object of this invention is to provide an underwater horn whose wall density is related to the frequency of sound being transmitted in a novel manner such that full acoustic loading is achieved on the surface of a vibratory structure when it is coupled to radiate sound through the horn opening.
- An additional object of this invention is to provide an underwater horn with a non-homogeneous wall structure wherein the horn will be free of self resonances in the frequency range of operation.
- FIGURE 1 is a perspective view showing one illustrative embodiment of the present invention, with parts broken away for clarity;
- FIGURE 2 is a longitudinal cross-sectional view showing one illustrative embodiment of this invention.
- FIGURE 3 is an enlarged detail view illustrating the mounting of an eletcromagnet transducer in a horn.
- FIGURE 4 shows a chart of experimental transmitting response curves measured underwater and illustrates the improved acoustic power output realized by the use of an underwater horn of the present improved design.
- t thickness of horn Wall in cm.
- d density of horn wall in gm./ cc.
- the material used in the construction of the horn be non-homogeneous in character to avoid resonance vibrations of the horn that were found to exist when the horn was constructed as a metallic shell.
- a metallic horn numerous resonant vibrations of the wall are excited during the passage of the sound which will interfere with the normal performance of the horn as an acoustic transformer.
- One of the non-homogeneous materials which may be advantageously used for the horn construction is an aggregate of concrete and scrap metal having an average density in the general neighborhood of lbs. to 300 lbs. per cu. ft. As is apparent, the density of the wall section of the horn is greater than the density of water.
- This range of density of the metal reinforced concrete is not critical to the operation of the improved horn, provided that the thickness of the wall is adjusted to satisfy the relationship indicated in Equation 1 for the frequency of operation.
- the passageway of the horn is flared or tapered so that the area of the opening increases by constant percentage increments for equal distances along the axis and that the large opening of the horn has an area which is greater than A /ZS where is the wavelength corresponding to the frequency being radiated.
- the numeral illustrates a transducer which is adapted to oscillate along a line parallel to the axis of the horn 11.
- the transducer may be of any conventional type that can operate underwater.
- One suitable type of structure is an electromagnetic transducer comprising an inertial inner mass which is flexibly suspended from and drives a rigid outer shell structure by virtue of oscillating magnetic forces generated between the inner and outer mass portions of the transducer.
- Further description of a satisfactory transducer for operating in deep water and which may be used as a transducer in combination with the underwater horn described in this invention is given in the copending application Ser. No. 334,203, now Patent No. 3,308,423, filed on Dec. 30, 1963, by Frank Massa, Jr., and entitled, Electroacoustic Transducer.
- the present invention is not concerned with the transducer design which is indicated generally by the numeral 10.
- the drawing illustrates the association of the vibrating surface of the transducer with the small opening of the horn 11.
- the transducer 10 is mounted so that it may be freely slid axially into the smooth tubular liner 12 which is part of the horn structure.
- the transducer 10 is held in place in horn 11 by means including resilient pads 15 that are held in place against surface 16 of transducer 10 by the annular clamping strips 18, which are fastened in position by the bolts 20.
- the horn 11 is preferably made of a non-resonant aggregate which may advantageously consist of cast concrete containing a filler of random-shaped pieces or bits of scrap metal.
- the bits of metal serve to increase the density of the horn structure and also serve to produce a non-homogeneous mass which will eliminate any predominant self-resonances that could occur in the bellshaped horn if the wall were fabricated of homogeneous material.
- the existance of any horn resonances within the desired frequency of operation could cause secondary sound radiation from the horn surfaces, which would interfere with the direct radiation of sound through the horn opening.
- the surface 24 defining the passage through the horn tapers or flares from the small opening 26 to the large opening 28.
- the cross-sectional area of the passageway increases exponentially from the small opening to the large opening, that is, the area increases by constant percentage increments for equal distances along the axis of the horn 11.
- FIGURE 4 shows a graph of experimental data taken underwater with a transducer having a piston approximately five inches in diameter which was designed for operation in the 2 kilocycle region.
- Curve A shows the measured sound pressure level at 1 yard distance from the transducer without the horn.
- the amplitude of transducer face at the highest point on the response curve was measured as .00015 inch peak to peak.
- Curve B shows the measured sound pressure level at 1 yard distance from the transducer and horn assembly mounted as illustrated in FIGURE 1.
- the horn used to obtain the data for curve B was cast with a scrap iron and concrete mixture having a density of approximately 200 lbs/cu. ft. and the wall thickness was adjusted to satisfy the approximate minimum requirement of Equation 1, namely, the mass of the wall was about 13 grams for each sq. cm. of area of the wall surface.
- Curve C shows the measured response with a horn having the same inner shape but the wall thickness was doubled such that the mass per unit area of the wall surface was approximately 26 gms./crn. or twice the minimum value indicated in Equation 1.
- a vibratory structure having a vibratory surface capable of performing oscillatory displacements, said vibratory surface characterized in that the square root of its area is less than /3 the wavelength of sound being radiated in the water by the vibrating surface, a horn structure made from a rigid non-homogeneous aggregate having a density greater than the density of water, said horn structure having a tapered passage along its length from a small opening at one end to a large opening at the other end, the small end of the horn structure being in close proximity to the vibratory surface of said vibratory structure for receiving the compressional waves created by said vibratory surface directly in the small opening of said horn structure.
- a vibratory structure having a vibratory surface capable of performing oscillatory displacements, said vibratory surface characterized in that the square root of its area is less than A the wavelength of sound being radiated in the water by the vibrating surface, a horn structure made from a rigid non-homogeneous aggregate having a density greater than the density of water, said horn structure having a tapered passage along its length from a small opening at one end to a large opening at the other end, the small end of the horn structure being in close proximity to the vibratory surface of said vibratory structure for receiving the compressional Waves created by said vibratory surface directly in the small opening of said horn structure, the cross-sectional area of the tapered horn passage increasing by constant percentage increments for equal linear distances along the axis of the horn structure from the small opening to the large opening, and the large opening of the horn having an area which is greater than V/ 25, where A is the wavelength of the sound being generated in the water by the vibratory surface.
- a vibratory structure having a vibratory surface capable of performing oscillatory displacements, said vibratory surface characterized in that the square root of its area is less than /3 the wavelength of sound being radiated in the water by the vibrating surface, a horn structure having a flared passage along its length from a small opening at one end to a large opening at the other end, the small end of the horn structure being in close proximity to the vibratory surface of said vibratory structure for receiving the compressional waves created by said vibratory surface directly in the small opening of said horn structure, the weight of the walls of the horn structure being greater than 25,000/f grams per sq. cm. of wall area, where f is the frequency of vibration of the vibratory surface in cycles per second.
- the horn structure is made from structural material comprising a rigid non-homogeneous aggregate having a density greater than the density of water.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Apparatuses For Generation Of Mechanical Vibrations (AREA)
Description
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US457701A US3360771A (en) | 1965-05-21 | 1965-05-21 | Underwater horn loudspeaker |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US457701A US3360771A (en) | 1965-05-21 | 1965-05-21 | Underwater horn loudspeaker |
Publications (1)
Publication Number | Publication Date |
---|---|
US3360771A true US3360771A (en) | 1967-12-26 |
Family
ID=23817782
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US457701A Expired - Lifetime US3360771A (en) | 1965-05-21 | 1965-05-21 | Underwater horn loudspeaker |
Country Status (1)
Country | Link |
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US (1) | US3360771A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3510698A (en) * | 1967-04-17 | 1970-05-05 | Dynamics Corp America | Electroacoustical transducer |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1126095A (en) * | 1909-05-12 | 1915-01-26 | Josef Schiessler | Transmitting apparatus for submarine signals. |
US1623561A (en) * | 1924-02-04 | 1927-04-05 | Westinghouse Electric & Mfg Co | Acoustic horn |
US2338262A (en) * | 1942-07-23 | 1944-01-04 | Jensen Radio Mfg Company | Acoustic horn |
US2447333A (en) * | 1931-12-30 | 1948-08-17 | Us Navy | Ultra-audible sound reception |
US2617874A (en) * | 1950-02-16 | 1952-11-11 | Pennsylvania Res Corp | System for the production of a high-pressure sound field |
-
1965
- 1965-05-21 US US457701A patent/US3360771A/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1126095A (en) * | 1909-05-12 | 1915-01-26 | Josef Schiessler | Transmitting apparatus for submarine signals. |
US1623561A (en) * | 1924-02-04 | 1927-04-05 | Westinghouse Electric & Mfg Co | Acoustic horn |
US2447333A (en) * | 1931-12-30 | 1948-08-17 | Us Navy | Ultra-audible sound reception |
US2338262A (en) * | 1942-07-23 | 1944-01-04 | Jensen Radio Mfg Company | Acoustic horn |
US2617874A (en) * | 1950-02-16 | 1952-11-11 | Pennsylvania Res Corp | System for the production of a high-pressure sound field |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3510698A (en) * | 1967-04-17 | 1970-05-05 | Dynamics Corp America | Electroacoustical transducer |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: DELLORFANO, FRED M. JR. Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:STONELEIGH TRUST, THE;REEL/FRAME:005397/0016 Effective date: 19841223 Owner name: MASSA PRODUCTS CORPORATION, 280 LINCOLN STREET, HI Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DONALD P. MASSA TRUST;CONSTANCE ANN MASSA TRUST;ROBERT MASSA TRUST;AND OTHERS;REEL/FRAME:005395/0971 Effective date: 19860612 Owner name: MASSA, DONALD P., COHASSET, MA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:STONELEIGH TRUST, THE;REEL/FRAME:005397/0016 Effective date: 19841223 Owner name: TRUSTEES FOR AND ON BEHALF OF THE D.P. MASSA TRUST Free format text: ASSIGN TO TRUSTEES AS EQUAL TENANTS IN COMMON, THE ENTIRE INTEREST.;ASSIGNORS:MASSA, DONALD P.;MASSA, CONSTANCE A.;MASSA, GEORGIANA M.;AND OTHERS;REEL/FRAME:005395/0942 Effective date: 19841223 Owner name: MASSA PRODUCTS CORPORATION, 80 LINCOLN STREET, HIN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DONALD P. MASSA TRUST;CONSTANCE ANN MASSA TRUST *;GEORGIANA M. MASSA TRUST;AND OTHERS;REEL/FRAME:005395/0954 Effective date: 19841223 |