Rotationally symmetric speaker array

Patent metadata

Field	Value
Publication number	US-10149046-B2
Application number	US-201415504312-A
Country	US
Kind code	B2
Filing date	Aug 18, 2014
Priority date	Aug 18, 2014
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A multi-way speaker array is disclosed that includes rings of transducers of different types. The rings of transducers may encircle the cabinet of the speaker array such that the speaker array is rotationally symmetric. The distance between rings of transducers may be based on a logarithmic scale. By separating rings of transducers using logarithmic spacing, denser transducer spacing at short wavelengths is achieved while limiting the number of transducers needed for longer wavelengths by spacing them in larger and larger logarithmic increments. Transducers with overlapping frequency ranges may be used in the speaker array to avoid initial dips or shortfalls in directivity for corresponding beam patterns.

First claim

What is claimed is:

1. A multi-way speaker array, comprising:
a cabinet for holding a plurality of transducers, wherein the cabinet is rotationally symmetric about a center axis;
a ring of transducers along a surface of the cabinet around the center axis, wherein the ring of transducers has a first frequency coverage;
an end transducer arranged on an end of the cabinet aligned with the center axis, wherein the end transducer has a second frequency coverage overlapping the first frequency coverage over a frequency range; and
a processor configured to drive the ring of transducers and the end transducer with an audio signal having frequency content within the frequency range to generate a beam pattern.

2. The multi-way speaker array of claim 1 , further comprising:
a second ring of transducers along the surface of the cabinet, wherein the ring of transducers is between the second ring of transducers and the end transducer.

3. The multi-way speaker array of claim 1 , wherein the end transducer is pointed perpendicular to the ring of transducers and the second ring of transducers.

4. The multi-way speaker array of claim 3 , wherein the second ring of transducers has a third frequency coverage.

5. The multi-way speaker array of claim 4 ,
wherein the third frequency coverage overlaps with the first frequency coverage and not the second frequency coverage.

6. The multi-way speaker array of claim 5 , wherein the cabinet is shaped as a cylinder.

7. The multi-way speaker array of claim 6 , wherein the ring of transducers is offset from the second ring of transducers in a direction of the center axis.

8. The multi-way speaker array of claim 7 , wherein a center of each transducer in the ring of transducers is aligned with a center of a respective transducer in the second ring of transducers to form N uniform columns of transducers, wherein the uniform columns of transducers encircle the cabinet such that the multi-way speaker array is rotationally symmetric on an order of N.

9. A multi-way speaker array, comprising:
a cabinet for holding a plurality of transducers, wherein the cabinet is rotationally symmetric about a center axis;
a first set of first transducers arranged in a first ring along a surface of the cabinet, wherein the first transducers have a first frequency coverage; and
a second set of second transducers arranged in a second ring along the surface of the cabinet, wherein the second transducers have a second frequency coverage overlapping the first frequency coverage over a frequency range; and
a processor configured to drive the first transducers and the second transducers with an audio signal having frequency content within the frequency range to generate a beam pattern.

10. The multi-way speaker array of claim 9 , further comprising:
a third set of third transducers arranged along the surface of the cabinet, wherein the second ring is between the first ring and the third set.

11. The multi-way speaker array of claim 9 , further comprising:
a third set of third transducers arranged in a third ring on an end of the cabinet around the center axis and pointed in a direction of the center axis perpendicular to the first set of first transducers and second set of second transducers.

12. The multi-way speaker array of claim 11 , wherein the first frequency coverage includes an upper limit, wherein the second frequency coverage includes a lower limit, and wherein the upper limit is above the lower limit.

13. The multi-way speaker array of claim 12 ,
wherein the third set of third transducers have a third frequency coverage that overlaps with the first frequency coverage and not the second frequency coverage.

14. The multi-way speaker array of claim 13 , wherein the cabinet is shaped as a cylinder.

15. The multi-way speaker array of claim 14 , wherein the first set of first transducers is offset from the second set of second transducers in the direction of the center axis.

16. The multi-way speaker array of claim 15 , wherein a center of each transducer in the first ring is aligned with a center of a respective transducer in the second ring to form N uniform columns of transducers, wherein the uniform columns of transducers encircle the cabinet such that the speaker array is rotationally symmetric on an order of N.

17. The multi-way speaker array of claim 9 , wherein each first transducer in the first ring is evenly spaced relative to adjacent first transducers in the first ring, and wherein each second transducer in the second ring is evenly spaced relative to adjacent second transducers in the second ring.

18. A method for driving one or more transducers in a speaker array, comprising:
receiving, by a speaker array, a first audio signal during a first time period, wherein the first audio signal has first frequency content, wherein the speaker array includes a ring of transducers along a surface of the cabinet around the center axis and an end transducer arranged on an end of the cabinet aligned with the center axis;
determining that the first frequency content is within a frequency overlap between the ring of transducers and the end transducer; and
generating, in response to determining that the first frequency content is within the frequency overlap, a beam pattern representing the first audio signal by the ring of transducers and the end transducer.

19. The method of claim 18 , further comprising:
receiving, by the speaker array, a second audio signal during a second time period, wherein the second audio signal has second frequency content different than the first frequency content;
determining that the second frequency content is not within the frequency overlap; and
generating, in response to determining that the second frequency content is not within the frequency overlap, the beam pattern representing the second audio signal by only one of the ring of transducers or the end transducer.

20. The method of claim 19 , wherein the speaker array includes a first audio crossover filter corresponding to the ring of transducers and a second audio crossover filter corresponding to the end transducer, wherein the first audio crossover filter has a first cutoff frequency and the second audio crossover filter has a second cutoff frequency, and wherein the frequency overlap is between the first cutoff frequency and the second cutoff frequency.

Assignees

• Apple Inc

Inventors

• Johnson Martin E
• Dix Gordon R
• Howes Michael B
• Geaves Gary P
• Saux Tom-Davy William Jendrik

Classifications

• H04R5/02

  Spatial or constructional arrangements of loudspeakers · CPC title

• H04R2201/401

  2D or 3D arrays of transducers · CPC title

• H04R1/403 Primary

  loud-speakers · CPC title

• H04R1/24

  Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges · CPC title

• H04R3/14

  Cross-over networks · CPC title