Multiple path acoustic wall coupling for surface mounted speakers
View Patent ↗A surface mounted loudspeaker design is provided that mitigates the interference between direct low frequency (LF) energy and reflected LF energy by breaking the LF energy from an LF driver into multiple paths using one or more of waveguides, driver load plates, and enclosure ports to diffuse the reflected energy and minimize frequency response errors. One or more embodiments of the present disclosure provides a loudspeaker have multiple acoustic exits strategically designed and located to generate, for example, three major wave front arrivals—2 source and 1 reflection—at target angles with favorable lag times, mitigating the cancellation notching and frequency errors that occur in conventional loudspeaker designs.
1. A loudspeaker comprising:
a speaker enclosure adapted for surface-mounting and including a front surface having at least one front acoustic exit facing a target direction and a rear surface having at least one rear acoustic exit adapted to face a wall surface; and
a low-frequency (LF) driver disposed in the speaker enclosure and adapted to emit LF acoustic energy that exits at least the front acoustic exit and the rear acoustic exit, the LF acoustic energy exiting the front acoustic exit and radiating directly in the target direction forming a first LF energy wave front, the LF acoustic energy exiting the front acoustic exit and reflecting off the wall surface forming a second LF energy wave front that lags the first LF energy wave front, the LF acoustic energy exiting the rear acoustic exit and radiating directly in the target direction combined with the LF acoustic energy exiting the rear acoustic exit and reflecting off the wall surface forming a third LF energy wave front that arrives between the first LF energy wave front and the second LF energy wave front.
2. The loudspeaker of claim 1 , wherein the first LF energy wave front has a magnitude of 0.80, the second LF energy wave front has a magnitude of 0.50 and lags the first LF energy wave front by 3.70 milliseconds, and the third LF energy wave front has a magnitude of 1.65 and lags the first LF energy wave front by 1.35 milliseconds.
3. The loudspeaker of claim 1 , wherein the speaker enclosure further comprises at least one side surface having a side acoustic exit, the LF acoustic energy exiting the side acoustic exit and radiating in the target direction forming part of the first LF energy wave front, the LF acoustic energy exiting the side acoustic exit and reflecting off the wall surface forming part of the second LF energy wave front that lags the first LF energy wave front.
4. The loudspeaker of claim 1 , wherein the speaker enclosure further comprises a bottom surface having a bottom acoustic exit, the LF acoustic energy exiting the bottom acoustic exit and radiating directly in the target direction combined with the LF acoustic energy exiting the bottom acoustic exit and reflecting off the wall surface forming part of the third LF energy wave front that arrives between the first LF energy wave front and the second LF energy wave front.
5. The loudspeaker of claim 1 , further comprising:
an LF waveguide coupled to the LF driver defining a first radiation path for the LF acoustic energy, wherein the at least one front acoustic exit includes the LF waveguide.
6. The loudspeaker of claim 5 , wherein the at least one front acoustic exit includes a front opening in the speaker enclosure above the LF waveguide.
7. The loudspeaker of claim 6 , the LF waveguide having a proximal opening positioned adjacent to the LF driver and extending away from the LF driver to a distal opening to define the first radiation path therethough, the proximal opening having a proximal opening area that is smaller than a radiating surface opening area to define a second radiation path for the LF acoustic energy around the LF waveguide and out the front opening.
8. The loudspeaker of claim 7 , further comprising:
a load plate directly in front of a bottom portion of the radiating surface and adjacent the LF waveguide to deflect a portion of the LF acoustic energy along a third radiation path to the rear acoustic exit.
9. A loudspeaker comprising:
a speaker enclosure including a front surface having a front acoustic exit, at least one side surface having a side acoustic exit, a rear surface having at least one rear acoustic exit, and a bottom surface having a bottom acoustic exit;
a low-frequency (LF) driver disposed in the speaker enclosure and having a radiating surface adapted to emit LF acoustic energy and a radiating surface opening defined by an outer circumference of the radiating surface;
an LF waveguide defining a first radiation path for the LF acoustic energy, the LF waveguide having a proximal opening positioned adjacent to the LF driver and extending away from the LF driver to a distal opening to define the first radiation path therethough, the proximal opening having a proximal opening area that is smaller than a radiating surface opening area to define a second radiation path for the LF acoustic energy around the LF waveguide and out the front acoustic exit and the side acoustic exit; and
a load plate directly in front of a bottom portion of the radiating surface and adjacent the LF waveguide to deflect a portion of the LF acoustic energy along a third radiation path to the rear acoustic exit and the bottom acoustic exit.
10. The loudspeaker of claim 9 , wherein a target axis of the loudspeaker is approximately 30° down from horizontal.
11. The loudspeaker of claim 9 , wherein a target axis of the loudspeaker is between 30° and 60° down from horizontal.
12. The loudspeaker of claim 9 , further comprising at least one high-frequency (HF) driver disposed in the speaker enclosure.
13. The loudspeaker of claim 12 , wherein the at least one HF driver comprises a first HF driver coupled to a first HF waveguide and a second HF driver coupled to a second HF waveguide.
14. The loudspeaker of claim 13 , wherein the LF waveguide, the first HF waveguide, and the second HF waveguide are formed from a triple waveguide body.
15. A method for radiating sound comprising:
providing a speaker enclosure including a front surface having at least one front acoustic exit facing a target direction and a rear surface having at least one rear acoustic exit adapted to face a wall surface;
providing a low-frequency (LF) driver disposed in the speaker enclosure and adapted to emit LF acoustic energy that exits at least the front acoustic exit and the rear acoustic exit;
generating a first LF energy wave front from the LF acoustic energy exiting the front acoustic exit and radiating directly in the target direction;
generating a second LF energy wave front that lags the first LF energy wave front from the LF acoustic energy exiting the front acoustic exit and reflecting off the wall surface; and
generating a third LF energy wave front that arrives between the first LF energy wave front and the second LF energy wave front from the LF acoustic energy exiting the rear acoustic exit and radiating directly in the target direction combined with the LF acoustic energy exiting the rear acoustic exit and reflecting off the wall surface.
16. The method of claim 15 , wherein the first LF energy wave front has a magnitude of 0.80, the second LF energy wave front has a magnitude of 0.50 and lags the first LF energy wave front by 3.70 milliseconds, and the third LF energy wave front has a magnitude of 1.65 and lags the first LF energy wave front by 1.35 milliseconds.
17. The method of claim 15 , wherein providing a speaker enclosure further comprises providing the speaker enclosure including at least one side surface having a side acoustic exit.
18. The method of claim 17 , wherein generating a first LF energy wave front comprises generating the first LF energy wave front from the LF acoustic energy exiting the front acoustic exit and side acoustic exit and radiating directly in the target direction.
19. The method of claim 17 , wherein generating a second LF energy wave front that lags the first LF energy wave front comprises generating the second LF energy wave front from the LF acoustic energy exiting the front acoustic exit and side acoustic exit and reflecting off the wall surface.
20. The method of claim 15 , wherein providing a speaker enclosure further comprises providing the speaker enclosure including a bottom surface having a bottom acoustic exit; and
wherein generating a third LF energy wave front that arrives between the first LF energy wave front and the second LF energy wave front comprises generating the third LF energy wave front from the LF acoustic energy exiting the rear acoustic exit and the bottom acoustic exit and radiating directly in the target direction combined with the LF acoustic energy exiting the rear acoustic exit and the bottom acoustic exit and reflecting off the wall surface.