Acoustics – Sound-modifying means – Housing or enclosure
Reexamination Certificate
2001-09-07
2004-01-13
Nappi, Robert (Department: 2837)
Acoustics
Sound-modifying means
Housing or enclosure
C181S148000, C181S155000, C381S345000, C381S352000, C381S160000
Reexamination Certificate
active
06675932
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to a speaker housing that minimizes standing waves and configured to resonate above an operating range of its transducers.
2. Related Art
In most loudspeaker systems, drivers or transducers are housed in a speaker enclosure. The speaker enclosure serves a number of functions. These functions include easier set up of transducers (or drivers) in one unit and keeping the transducers in the correct position while working together. At the same time, speaker enclosures often affect the quality of sound produced by the transducers. As the transducers vibrate the diaphragm, sound waves are emitted in the back and forth direction relative to the transducer. In other words, sound is produced behind the diaphragm as well as in front of the diaphragm. In a sealed enclosure, no air can escape and therefore back waves are trapped within the enclosure. Because no air can escape, the interior air pressure of the sealed enclosure changes as the diaphragm vibrates. With today's sealed enclosures, these back waves can significantly affect the quality of sound produced by the transducers.
One of the problems with back waves is that standing waves may be formed within the enclosure. For example, within rectangular-like box enclosures, there are a number of parallel surfaces, and as back waves emanate within the parallel surfaces, the standing waves simply propagate back and forth causing negative audible artifacts. The anomalies caused by standing waves are typically one-note based and are objectionable to the listener.
Another problem associated with back waves is viration of the waves against the sidewalls of the enclosure. Depending on the size and structural integrity of the sidewalls, the back waves may resonate at approximately the same operating frequency of the transducers. In such a case, the vibration of the sidewalls can interfere with the quality of sound produced by the transducer. Thus, the overall loudspeaker system may operate at less efficiency because some of the energy is used to vibrate the sidewalls instead of the diaphragm. Accordingly, there is still a need for a speaker enclosure that can minimize or defuse standing waves and prevent the enclosure from resonating within the operating frequency range of its transducers.
SUMMARY
This invention provides a speaker enclosure that minimizes or defuses standing waves and minimizes resonance within the operating frequency range of its transducers. This is accomplished by providing a speaker enclosure formed from a number of inner surfaces where no two surfaces are parallel with respect to another surface. In other words, none of the inner surfaces of the enclosure are parallel with respect to each other minimizing the propagation of standing waves. If standing waves do occur, they are diffused quickly by the elimination of parallel surfaces. Furthermore, a sidewall or inner surface that is prone to resonate within the operating frequency of its transducers may be strengthened, via ribs or any other methodologies known to one skilled in the art, to prevent that sidewall from vibrating.
Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
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Manrique Pedro
Wathen David
Harman International Industries, Inc.
Martin Edgardo San
Nappi Robert
Squire Sanders & Dempsey L.L.P.
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