# US 2009/0268554 A1 · Underwater sound projector system and method of producing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2009/0268554 A1 - Document ID: US20090268554A1 - Status: Published application - Kind: A1 - Application number: 11/794,771 - Filed: 2005-12-23 - Published: 2009-10-29 - Earliest claimed: 2005-01-06 - Assignees: Ultra Electronics Canada Defence Inc. - Inventors: Bruce Allan Armstrong - Web page: https://patentgrep.com/patent/US20090268554A1 ## CPC - B06B 1/0618: {of piezo- and non-piezoelectric elements, e.g. 'Tonpilz'} - H04R 1/44: Special adaptations for subaqueous use, e.g. for hydrophone - B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract An underwater sound projector system comprises multiple sound projectors, each sound projector being capable of producing acoustic pressures. The sound projectors are held in close proximity such that the sound projectors interact with one another via the acoustic pressures produced. In embodiments, the number and/or spacing of the sound projectors are adjusted based on target performance parameters. ## Claims ### Claim 1 A method for producing an underwater sound projector system, the method comprising the steps of: providing multiple sound projectors, each sound projector being capable of producing acoustic pressures; and holding the sound projectors in close proximity such that a separation distance between a centre of one sound projector and a centre of a neighbouring sound projector is equal to or less than λ/8, wherein λ is a wavelength of an acoustic wave of the sound projector system at a system resonance frequency. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the holding step holds the sound projectors in close proximity to increase the radiation impedance felt by each sound projector. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the holding step holds the sound projectors in places determined by target performance parameters, the target performance parameters including a resonance frequency, source level, cavitation depth, electroacoustic efficiency and/or bandwidth. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the providing step comprises the step of determining a number of the sound projectors based on one or more target performance parameters; and the holding step holds the determined number of sound projectors in close proximity. ### Claim 5 (depends on 4) The method as claimed in claim 4, further comprising the step of: altering the number of sound projectors based on a different target parameter. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the providing step comprises the step of determining a distance between the sound projectors based on one or more target performance parameters; and the holding step holds the sound projectors separated by the determined distance therebetween. ### Claim 7 (depends on 6) The method as claimed in claim 6, further comprising the step of: altering the distance between the sound projectors based on a different target parameter. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein the holding step holds some or all of the sound projectors into one or more stacks. ### Claim 9 (depends on 8) The method as claimed in claim 8, wherein the holding step holds some or all of the sound projectors into one or more stacks in axial alignment. ### Claim 10 (depends on 8) The method as claimed in claim 8, wherein the holding step holds the stacks in close proximity such that the sound projectors of the stacks interact with one another via the acoustic pressures that the projectors produce. ### Claim 11 An underwater sound projector system comprising: multiple sound projectors capable of producing acoustic pressures; and means for holding the sound projectors in close proximity such that a separation distance between a centre of one sound projector and a centre of a neighbouring sound projector is equal to or less than λ/8, wherein λ is a wavelength of an acoustic wave of the sound projector system at a system resonance frequency. ### Claim 12 (depends on 11) The underwater sound projector system as recited in claim 11, wherein each sound projector is a flexural plate projector comprising: a bending assembly having two bending members capable of vibrating when the bending members are subjected to an alternating voltage, the bending members being held together with a gap therebetween to permit vibration of the bending members; a flexible case for encasing the bending assembly to electrically insulate the bending assembly from water, the flexible case allowing vibration of the bending members; and electrical members connected to the bending members for providing alternating voltages. ### Claim 13 (depends on 12) The underwater sound projector system as recited in claim 12, wherein each of the bending members comprises a piezoelectric ceramic plate affixed to a metal plate, preferably aluminum; and the electrical members include a first electrical wire connected to the metal plate, and a second electrical wire connected to the ceramic plate. ### Claim 14 (depends on 11) The underwater sound projector system as recited in claim 11, wherein the means for holding includes a holder for holding the sound projectors in place based on target performance parameters, the target performance parameters including a resonance frequency, source level, cavitation depth, electroacoustic efficiency and/or bandwidth. ### Claim 15 (depends on 11) The underwater sound projector system as recited in claim 11, wherein the means for holding includes a holder for holding the sound projectors in close proximity to increase a radiation impedance felt by each sound projector. ### Claim 16 (depends on 11) The underwater sound projector system as recited in claim 11, wherein the multiple sound projectors include a predetermined number of the sound projectors, the predetermined number being determined based on one or more target performance parameters. ### Claim 17 (depends on 11) The underwater sound projector system as recited in claim 11, wherein the means for holding separates the sound projectors by a predetermined distance therebetween, the predetermined distance being determined based on one or more target performance parameters. ### Claim 18 (depends on 11) The underwater sound projector system as recited in claim 11, wherein the means for holding including one or more spacers for separating the sound projectors. ### Claim 19 (depends on 16) The underwater sound projector system as recited in claim 16, wherein the spacers allow some or all of the sound projectors to be arranged into one or more stacks. ### Claim 20 (depends on 16) The underwater sound projector system as recited in claim 16, wherein the spacers allow some or all of the sound projectors arranged into one or more stacks in axial alignment. ### Claim 21 (depends on 17) The underwater sound projector system as recited in claim 17, wherein the means for holding including a frame for holding the stacks of sound projectors in close proximity such that the sound projectors of the stacks interact with one another via the acoustic pressures that the projectors produce. ### Claim 22 (depends on 1) The underwater sound projector system as recited in claim 1, wherein each of the multiple sound projectors comprises a bending assembly having two bending members capable of vibrating when the bending members are subjected to an alternating voltage, the bending members being held together with a gap therebetween to permit vibration of the bending members; and the underwater sound projector further comprises: a flexible container for containing the multiple sound projectors; an electrically insulating fluid contained in the flexible container; and wherein the multiple sound projectors are immersed in the electrically insulating fluid in the flexible container. ### Claim 23 (depends on 1) The method as recited in claim 1, wherein the providing step provides the multiple sound projectors, each multiple sound projector being encased in a flexible case. ### Claim 24 (depends on 1) The method as recited in claim 1 further comprising the step of: encasing the multiple sound projectors in a flexible container containing an electrically insulating fluid. ### Claim 25 (depends on 1) The method as recited in claim 1, wherein the providing step provides the multiple sound projectors, one or more of the sound projector having a predetermined resonance frequency; and the holding step holds the sound projectors such that the underwater sound projector system has a lower resonance frequency than the predetermined resonance frequency. ### Claim 26 (depends on 11) The underwater sound projector system as recited in claim 11, wherein one or more of the sound projectors have a predetermined resonance frequency; and the underwater sound projector system has a lower resonance frequency than the predetermined resonance frequency. ### Claim 27 (depends on 25) The method as recited in claim 25, wherein the providing step provides the multiple sound projectors, the one or more of the sound projector having a predetermined transmitting voltage response at the predetermined resonance frequency; and the holding step holds the sound projectors such that the underwater sound projector system has a higher transmitting voltage response than the predetermined transmitting voltage response at the lower resonance frequency. ### Claim 28 (depends on 26) The underwater sound projector system as recited in claim 26, wherein the one or more of the sound projectors have a predetermined transmitting voltage response at the predetermined resonance frequency; and the underwater sound projector system has a higher transmitting voltage response than the predetermined transmitting voltage response at the lower resonance frequency. ### Claim 29 (depends on 1) The method as recited in claim 1, wherein the providing step provides the multiple sound projectors, one or more of the sound projector having a predetermined bandwidth; and the holding step holds the sound projectors such that the underwater sound projector system has a greater bandwidth than the predetermined bandwidth. ### Claim 30 (depends on 11) The underwater sound projector system as recited in claim 11, wherein one or more of the sound projectors have a predetermined bandwidth; and the underwater sound projector system has a greater bandwidth than the predetermined bandwidth. ### Claim 31 (depends on 1) The method as recited in claim 1, wherein the providing step provides the multiple sound projectors, one or more of the sound projector having predetermined efficiency; and the holding step holds the sound projectors such that the underwater sound projector system has greater efficiency than the predetermined efficiency at and below a resonance frequency of the underwater sound projector system and at most frequencies above the resonance frequency. ### Claim 32 (depends on 11) The underwater sound projector system as recited in claim 11, wherein one or more of the sound projectors have predetermined efficiency; and the underwater sound projector system has greater efficiency than the predetermined efficiency at and below a resonance frequency of the underwater sound projector system and at most frequencies above the resonance frequency. ### Claim 33 (depends on 1) The method as recited in claim 1, wherein the holding step holds the sound projectors such that the underwater sound projector system has a predetermined cavitation depth. ### Claim 34 (depends on 11) The underwater sound projector system as recited in claim 11, wherein the underwater sound projector system has a predetermined cavitation depth.