Patent EA-002176-B1 (EA)
Title: Sound radiating devices/systems
Inventor: BANK GRAHAM
IPC: H04R17/00
Filed: 1998-07-30
Abstract: 1. Sound radiator comprising an areally distributed array of plural acoustic transducers having individually energisable drive means, means for providing phase-different drive signals resulting in phase-different sound radiations from the acoustic transducers, characterised in that the drive signal providing means is operative to apply to said drive signals a distribution of phasing over the area of the array that is randomised to achieve diffuse overall sound radiation. 2. Sound radiator according to claim 1, wherein the drive signal providing means is operative to apply phase-different said drive signals to said drive means with a distribution of phasing that is disorderly over the area of the array to achieve incoherent sound radiation. 3. Sound radiator according to claim 1 or 2, wherein the drive signal providing means is operative to impose different phasing to substantially the same frequency content of an input signal. 4. Sound radiator according to any preceding claim, wherein differences of phase concerned are other than whole number submultiples or divisors of 180 degree . 5. Sound radiator according to any preceding claim, wherein phase differences concerned have up to one-to-one unique correspondence with the transducers, respectively. 6. Sound radiator according to any preceding claim, wherein the drive signal providing means is operative as aforesaid for acoustic frequency content above lower frequencies for which the drive signal providing means is further operative to cause in-phase sound radiations from at least some of the acoustic transducers. 7. Sound radiator according to claim 6, wherein said i some acoustic transducers are of sub-area(s) of the array. 8. Sound radiator according to claim 6 or claim 7, wherein said some acoustic transducers are substantially central of the array. 9. Sound radiator according to any one of claims 6 to 8, wherein said at least some acoustic transducers are greater in number and corresponding said sub-area(s) of the array greater in size the lower the acoustic frequencies concerned. 10. Sound radiator according to any one of claims 6 to 9, wherein the drive signal providing means has associated filter means for said lower frequency acoustic content of an input signal or bands thereof. 11. Sound radiator according to any preceding claim, wherein said array has at least 20 said acoustic transducers. 12. Sound radiator according to any preceding claim, wherein said array has up to 750 or more said acoustic transducers. 13. Sound radiator according to any preceding claim, wherein said acoustic transducers are of pistonic-action type. 14. Sound radiator according to any preceding claim, wherein said acoustic transducers are of cone-drive type. 15. Sound radiator according to any one of claims 1 to 12, wherein said acoustic transducers are of electrostatic type. 16. Sound radiator according to any one of claims 1 to 12, wherein said acoustic transducers are of piezoelectric type. 17. Sound radiator according to any one of claims 1 to 12, wherein said acoustic transducers are of electro-mechanical film type. 18. . Sound radiator according to any preceding claim, wherein said acoustic transducers have associated carrier means common to all or groups thereof.