Patent Application
20060059801
The present invention relates generally to noise and acoustic control and in particular the present invention relates to acoustically intelligent structures with resonators.
Noise pollution is an ever-increasing problem. Noise from automobiles, airplanes, trains, power equipment, animals, electronics and computers in office areas or homes, etc. passes though the walls and windows of spaces used for human occupation or living, such as workplaces, homes, schools, churches, and various shelters. The noise interferes with our ability to hear, sleep, perform, may cause fatigue, etc. Noise insulation has been used in walls to mitigate noise transmission, but often targets a rather small range of noise frequencies.
One technique for reducing noise transmission through a window involves a double-paned window with each of the panes having a different thickness for blocking out noise over a broader range of frequencies than two-paned windows with panes having the same thickness. Another technique involves a two-paned window with each of the panes having a different density for blocking out noise over a broader range of frequencies than two-paned windows with panes having the same density. For some techniques, a vibration dampening material is disposed between two windowpanes of different thickness and/or density for dampening vibrations of either windowpane. One problem with these techniques for reducing sound transmission through windows is that they usually require increased frame sizes and more glass compared to conventional two-paned windows, which results in increased costs. Also, these techniques may result in relatively heavier windows and thus may be more difficult to install than conventional windows. Moreover, these techniques are limited to two-paned windows. Depending on the required acoustic property of a window, the cost of that window may increase by 30% to 60% when compared to non-acoustic windows.
Another technique for reducing sound transmission through a window involves laminated windowpanes for reducing sound transmission. However, laminated windowpanes are more expensive than non-laminated windows, e.g., usually about 30 to 60 percent more expensive. Moreover, laminated windows and two-paned windows having panes of different density may alter optical properties of the window.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative noise reduction methods.
The above-mentioned problems with noise reduction and other problems are addressed by the present invention and will be understood by reading and studying the following specification.
Embodiments of the invention provide structures, such as walls, furniture, windows, etc., that have one or more resonators, e.g., Helmholtz resonators, for absorbing noise at their resonant frequencies.
One embodiment of the invention provides a wall having a plurality of structural elements. One or more structural elements of the plurality of structural elements have a resonator therein. The resonator has an opening. The one or more first structural elements include an adjustable shutter for varying a size of the opening.
Another embodiment of the invention provides a window having a frame, one or more windowpanes disposed within the frame, and one or more resonators connected to the frame.
Another embodiment of the invention provides a table having a top with one or more resonators and a plurality of legs connected to the top.
Another embodiment of the invention provides a rack having a plurality of posts. One or more of the posts include a resonator. Two or more shelves are connected to the plurality of posts.
Another embodiment of the invention provides a chair having a seat, a back connected to the seat, and one or more resonators connected to either the seat or the back.
Another embodiment of the invention provides a bookcase with a frame having one or more resonators. A book container is connected to the frame.
Another embodiment of the invention provides a noise reduction method that includes receiving noise at a monitor, transmitting a signal representative of the noise to a controller, and adjusting a resonant frequency of one or more first resonators of a structure to a frequency of the noise using the controller in response to receiving the signal at the controller.
Further embodiments of the invention include methods and apparatus of varying scope.
In the following detailed description of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims and equivalents thereof.
For one embodiment, the structural elements 102 and 104 are selected to absorb noises of different frequencies from different noise sources or different harmonics of noise from a single noise source. However, for another embodiment, the structural elements 102 and 104 may be selected to absorb substantially the same noise from a single noise source.
For one embodiment, a size (or cross-sectional area) of opening 130 is adjustable, e.g., using a manually or electro-mechanically actuated shutter 140 (
For other embodiments, Helmholtz resonators 260, each having an opening 262, are connected to seat 210. For another embodiment, Helmholtz resonators 280, each having an opening 282, are connected to back 220. For one embodiment, one or more of openings 232, 252, 262, and 282 are adjustable, e.g., using a manually or electro-mechanically actuated shutter, for tuning the respective resonator. For other embodiments, seat 210 and/or back 220 may be formed from Helmholtz resonators, e.g., as described for structure 100 of
For one embodiment, a damping material, such as damping material 115 of
Control system 1200 includes a controller 1210 having an output electrically connected to an input of each of one or more actuators 1220. Each actuator is adapted to vary a geometrical parameter of a respective one of Helmholtz resonators 1205, such as a size of an opening 1230 of that Helmholtz resonator 1205 and/or a volume of that Helmholtz resonator 1205 for varying the resonant frequency of that Helmholtz resonator 1205. Specifically, each actuator 1220 is mechanically coupled to a shutter 1240 of a respective one of Helmholtz resonators 1205 for varying a size of an opening 1230 of that Helmholtz resonator 1205 and/or a piston or one or more partitions for varying a volume of that Helmholtz resonator 1205. Each actuator 1220 may include a stepper motor, a solenoid, or the like, for moving its respective shutter 1240 and/or piston or partitions in response to a control signal from controller 1210. For one embodiment, a monitor 1250, such as a microphone, has an output electrically connected to an input of controller 1210. For one embodiment, monitor 1250 is an integral component of controller 1210. For other embodiments, monitor 1250 may include a plurality of microphones distributed around a space containing one or more of the structures described above.
For one embodiment, controller 1210 respectively sends one or more control signals to the one or more actuators 1220. For one embodiment, each of the one or more actuators 1220 sets the respective one or more Helmholtz resonators 1205 to the same resonant frequency. For another embodiment, actuators 1220 set their respective Helmholtz resonators 1205 to different resonant frequencies, e.g., corresponding to noises of different frequencies from different noise sources or to different harmonics of a single noise from as single noise source. For various embodiments, controller 1210 outputs the control signals in response direct user inputs.
For some embodiments, controller 1210 outputs the control signals in response to monitor 1250. Specifically, for one embodiment, monitor 1250 receives noise and outputs an electrical signal to controller 1210 that is representative of the noise. Controller 1210 evaluates the electrical signal, e.g., by determining one or more peaks respectively corresponding to noise frequencies from a power spectrum of the noise. Controller 1210 instructs the one or more actuators 1220 to adjust their respective Helmholtz resonators 1205 to one or more of these noise frequencies. The process may be repeated to determine whether the one or more noise frequencies have been attenuated and for readjusting resonators 1205, if necessary. For one embodiment, controller 1210 has a look-up table that includes opening sizes and/or resonator volumes tabulated against resonant frequencies of Helmholtz resonators 1205, and controller 1210 enters the table with a resonant frequency and the table outputs an opening size and/or resonator volume in response to that frequency.
If there is more than one peak in the power spectrum, e.g., first and second peaks respectively corresponding to first and second noise frequencies, one or more Helmholtz resonators 1205 are set to the first frequency and one or more Helmholtz resonators 1205 are set to the second frequency. The process is repeated to determine whether the first and second frequencies have been attenuated and for readjusting the resonators, if necessary.
Embodiments of the invention provide structures, such as walls, furniture, windows, etc., that have one or more resonators, e.g., Helmholtz resonators, for absorbing noise at their resonant frequencies. For one embodiment, a structure has one or more first resonators for absorbing noise having a first frequency substantially the same as a resonant frequency of the one or more first resonators. The resonant frequency of each of the one or more first resonators may be adjusted by adjusting a size of an opening and/or a volume of that first resonator. The size of the opening and/or the volume may be manually controlled or may be controlled by a controller in response to a noise monitor. One or more second resonators may also be included for absorbing noise having a second frequency substantially the same as a resonant frequency of the one or more second resonators.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. Many adaptations of the invention will be apparent to those of ordinary skill in the art. Accordingly, this application is intended to cover any adaptations or variations of the invention. It is manifestly intended that this invention be limited only by the following claims and equivalents thereof.
