Patent Publication Number: US-7908924-B2

Title: Sound focusing mechanism and method of estimating acoustic leakage of an object and method of estimating transmission loss of an object

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application relates to and claims priority to U.S. Provisional Application No. 60/479,189, entitled “Sound Focusing Mechanism and Method of Determining Acoustic Leakage of an Object and Method of Determining the Transmission Loss of an Object,” filed on Jun. 18, 2003, the disclosure of which is specifically incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sound focusing mechanism that generates a high sound pressure level, denoted throughout this document as decibel, and highly focused signal that is used in connection with sound proofing to locate areas of acoustic leakage. The sound focusing mechanism is also used in connection with the determination of the transmission loss of an object. The present invention is also directed to a method of locating acoustic leakage points in an object in order to improve sound proofing by focusing a high decibel sound at a desired location on an object then measuring the sound transmission loss at one or more locations. The present invention is also directed to a method of determining the transmission loss of an object or structure that can be simply performed by a single individual. 
     2. Description of Related Art 
     Hearing sounds from adjacent rooms, pipes, outside the dwelling or adjacent dwellings is something that many people experience on a daily basis. At a minimum, it can be distracting. Many spend large sums of money to reduce the overall transmission of sound into and/or through their dwellings in order to create quieter and calmer surroundings. This, however, does not always produce the desired results. In many circumstances, the person(s) performing the acoustic modifications to the structure does not provide adequate sound insulation or improperly installs the same such that the annoying sounds and noises are still transmitted through the structure. 
     The problem encountered by many of these installers is that it is often difficult to determine the location of acoustic leaks. To date, an economical device to permit someone to easily determine the transmission loss of a wall, floor, or other room perimeter structures or simply locate acoustic leaks in the same so that it is possible to determine what are the optimum actions to be taken to increase the transmission loss of a wall, ceiling, window, pipe, or other structural element has not been developed. 
     SUMMARY OF THE INVENTION 
     In response to the foregoing challenges, applicants have developed an innovative sound focusing mechanism for generating a focused source of sound, which can be used to identify the transmission loss of an object or identify areas of acoustic leakage. In accordance with the present invention, the sound focusing mechanism includes a housing. The housing includes at least one wall formed from a material having high sound insulating properties. The at least one wall defines a central cavity. One end of the cavity is open. The sound focusing mechanism includes a sound generating device for generating a high decibel sound, which is located within the central cavity. An actuator assembly is operatively connected to the sound generating device for selectively operating the sound generating device. The at least one wall is configured to limit the transmission of the sound there through such that a focused beam or pulse sound is emitted from the mechanism through the opening. 
     The sound focusing mechanism includes an activation controller. This controller can be a simple button, switch or a computer controller. The computer controller selectively controls the operation of the sound generating device. The computer controller modifies the decibel level of the sound generated by the noise generating device, or controls the duration of the sound generated by the sound generating device, or controls the frequency, or controls the type of signal. 
     Applicants have also developed an innovative method of determining the sound transmission loss of an object. The method includes generating a sound with a predetermined decibel level using a sound focusing mechanism and directing the source of sound on one side of the object such that the transmission of sound is substantially localized onto the object. Directing the source of sound on one side of the object includes the positioning of an opening in the sound focusing mechanism at a desired location on the object. The decibel level of sound is then measured on an opposite side of the object. The measured decibel level is then compared to the predetermined decibel level to the measured decibel level to estimate the transmission loss for the object. Based upon the estimated transmission loss, it is possible to estimate, determine and/or identify measures for improving transmission loss of the object based upon the measured transmission loss. Such measures may include adding additional layers of sound insulating material. 
     In accordance with the present invention, it is contemplated that the sound focusing mechanism may be repositioned at various locations on the object to identify variations in transmission loss within the object. 
     Applicants have also developed an innovative method of locating acoustic leakage points along an object. Once acoustic leakage points have been identified, it is possible to propose measures including but not limited to additional layers of sound insulating material for reducing leakage, or acoustically sealing a compromise in an acoustic installation, such as a wall outlet. The method further includes generating a sound having a predetermined decibel level using a sound focusing mechanism and directing the source of sound into the object such that the sound is substantially localized on the object. The decibel level of sound emitted from the object is then measured at various locations along the object. From the measured levels, areas of higher noise emission are identified. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein: 
         FIG. 1  is a schematic view of a sound focusing mechanism in accordance with the present invention having an actuator assembly in accordance with one embodiment of the present invention; 
         FIG. 2  is a side cross-sectional view of the sound focusing mechanism of  FIG. 1 ; 
         FIG. 3  is bottom view of the sound focusing mechanism of  FIG. 1 ; 
         FIG. 4  is a schematic view of a sound focusing mechanism in accordance with the present invention having an actuator assembly in accordance with another embodiment of the present invention; 
         FIG. 5  is a schematic view of a sound focusing mechanism in accordance with the present invention having an actuator assembly in accordance with another embodiment of the present invention; and 
         FIG. 6  is a partial schematic view of the layers of high sound transmission class material forming the walls of the sound focusing mechanism according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     A sound focusing mechanism  1  in accordance with the present invention will now be described in greater detail in connection with  FIGS. 1-5 . The sound focusing mechanism  1  described herein will be used to determine the transmission loss of an object such as a wall, ceiling or other structure. The sound focusing mechanism  1  produces a sound that can be substantially localized onto or into an object. The sound focusing mechanism  1  will be used to locate and identify acoustic leakage points in a structure, including but not limited to walls, ceilings, floors, pipes, windows, etc. In either case, the mechanism  1  provides the individual with a simple means for locating areas of poor transmission loss or areas of high acoustic leakage so that possible remedies be readily identified and localized. From the determination of the leakage points or transmission loss, it is possible for the person or persons performing acoustic modifications on the structure to identify certain remedies for reducing leakage and improve transmission loss. 
     The sound focusing mechanism  1  includes a cylindrically shaped container or housing  10  having an end wall  11 , which can include an access panel  15  for providing access to a sound generating device  20  and a possible battery, and at least one side wall  12 . A passageway or channel or cavity  13  is formed by the end wall  11  and the at least one side wall  12 . The housing  10  further includes an opening  14  formed in one end. Alternatively, the container  10  may take various shapes and forms including but not limited to a cylindrical shaped container, a box shaped container or any other shape having an opening formed such that opening can be positioned against a desired surface so that a high decibel level of sound can be focused onto the surface. 
     Located within the housing  10  is a sound generating device  20 . The access panel  15  provides access to the sound generating device  20  and battery assembly, which may be combined as a single unit. The access panel  15  can be threadably attached to the housing  10  or snap fit into the housing  10 . The sound generating device  20  is preferably located within the interior of the housing or container  10  on the end wall  11 . The location of the sound generating device  20  may vary within the channel  13  provided the sound emitted from the sound generating device  20  is directed toward the opening  14  in the container  10 . The sound generating device  20  can be a noisemaker that is capable of emitting a sound of 110 db. Alternatively, the noisemaker can emit various sound emitting sound pressure levels including those above and/or below 110 db. Additionally, the sound generating device  20  can be capable of emitting a single high frequency sound or low frequency sound. The noise generating device  20  can be capable of being programmed to emit different types of sound, such as a pure tone, white noise or sweeping through specified frequencies depending on the desired testing conditions. The frequency range can include a range of 50 Hz to 5,000 Hz in accordance with the American Society for Testing and Materials (ASTM) E90 standard discussed below. A computer controller  40  can be used to perform this function. 
     The sound generating device  20  generates a known type of high decibel noise. The container  10  is designed to direct the sound towards the opening  14  and outwardly there from. While a certain amount of sound is transmitted through the walls  12  of the housing  10 , this arrangement substantially localizes the transmission of the sound into a desired area in the object. The container  10  is formed from a material with a high STC rating. STC stands for “sound transmission class” and is a single number rating derived from measured values of sound transmission loss in accordance with the American Society for Testing and Materials (ASTM) E90 standards. The transmission loss through an object is a measure of its effectiveness in preventing the sound power incident on one side of the object from being transmitted through it and radiated on the other side. The STC provides a single number estimate of an object&#39;s performance for certain common sound reduction applications. In general, materials having low STC ratings have very low transmission losses. For example, a wall having a field tested STC rating between 20-22, most sentences are clearly understood by an individual in another room on the other side of that wall. With a STC rating between 25-27, many phrases and some sentences can be understood without straining to hear. With a STC rating between 30-32, it is possible to clearly hear and understand some individual words and occasional phrases. With a STC rating between 35-37, medium decibel level speech is audible and occasional words are understood. With a STC rating between 40-42, loud speech and music is audible. With a STC rating between 45-47, loud speech is audible but requires straining to hear. Loud music can be heard and may be disturbing. With a STC rating between 50-52, loud speech is essentially inaudible. Music can be heard faintly but base frequencies may be audible and possibly an annoyance. With STC ratings above 55, music may be heard faintly such that base frequencies “thump.” Loud low frequency music may still be heard very faintly if played loud with a STC rating of 60 or more. Most air-borne noise sources are effectively blocked to eliminate noise with ratings above 65. 
     The housing or container  10  can be formed from a material having a high STC, such as for example, a one pound per square foot loaded vinyl. The STC rating for the container  10  needs to be at least 30. The STC rating is preferably 40 or greater, but rarely higher than 60. The sound generating device  20  can be calibrated such that the noise emitted from the opening  14  of the housing  10  can be calibrated using a decibel (“db”) meter. In one form, the high STC material may be formed as sheets  2 . The sheets  2  may be stacked or laminated together, as shown in  FIG. 2  and  FIG. 6 , to produce the desired STC of container  10  so that sound transmission through the end wall  111  and the at least one side wall  12  is minimized so that noise only exits the container  10  from the opening  14 . Each layer  2  increases the overall STC of the housing  10 . It is contemplated that a certain amount of sound will be transmitted through the walls  11  and  12  of the container  10 , but at a significantly lower decibel than the sound exiting the opening  14 . Alternatively, the container walls  11  and  12  may be molded from the high STC material, where the thickness of the wall is determined by the desired level of transmission loss. Using a molding process, it is possible to produce containers  10  having varying shapes and sizes. 
     The sound focusing mechanism  1  further includes an actuator assembly  30 . The actuator assembly  30  is operatively connected to the noise generating device  20  to selectively operate the noise generating device  20 . The actuator assembly  30  can take various forms. The actuator assembly  30  can be simple actuator knob or button  31  located on the end wall  11  on the outside of the container  10 , as shown in  FIG. 1 . With such an arrangement, the operator merely presses or operates the knob to generate a sound for a small duration of time or a continuous sound of type, such as a pure tone, or broadband noise. When a continuous sound is produced, it is contemplated that a subsequent operation of the actuator assembly  30  is necessary to discontinue the sound. While this arrangement, produces a compact sound focusing mechanism  1 , the use of such an actuator assembly  30  does present one notable drawback. In particular, the tester must return to the mechanism  1  every time it is desirable to produce a pulse of sound. 
     The actuator assembly  30  can be capable of remote activation. The actuator assembly  30  can include a remote control  32  that is hard wired to the container  10 , as shown in  FIG. 4 . While such an arrangement permits remote activation, the distance the operator can travel from the mechanism  1  is limited. A radio controlled remote control  33  is illustrated in  FIG. 5 . With such an arrangement, the operator is free to travel away from the mechanism  1  while operating the mechanism  1  at any location. 
     The sound focusing mechanism  1  may include a computer controller  40 . The controller  40  permits the operator to vary the signal type, duration and decibel level pattern of the sound generating device  20 . The computer controller  40  can be used in connection with any of the above-described actuator assemblies  30 . The sound generating device  20  is operatively connected to the controller  40 . Furthermore, the actuator assembly  30  is operatively connected to the controller  40  to control the operation of the device  20  and/or the controller  40 . 
     The operation of the sound focusing mechanism  1  in connection with the determination of the transmission loss of an object will now be described in greater detail. The measurement of the transmission loss will be described in connection with the measurement of the transmission loss of a wall. The method is not intended to be limited to the measurement of the transmission loss of a wall. The sound focusing mechanism  1  and the method described herein can be used to estimate the transmission loss of almost any object. 
     Prior to locating the opening  14  of the sound focusing mechanism  1  against a wall of a structure, the sound focusing mechanism  1  can be operated to calibrate the decibel level of the sound generated by the sound generating device  20 . A decibel meter can be used to take such a measurement. Once the decibel level of the sound generating device  20  is determined, the opening  14  of the container  10  is located against the wall or ceiling or the mechanism  1  can simply be held in place by an assistant. The container housing  10  can include some type of removable adhesive or other fastener or support stand or bracket to temporarily locate and secure the mechanism  1  at a desired location on the wall. The device  20  is then operated using the actuator assembly  30 . The sound emitted by the device  20  is substantially localized or focused into the wall. The decibel meter is then positioned on the opposite side of the wall. The decibel level on the opposite side of the wall is measured using the decibel meter to determine the transmission loss. For example, the sound focusing mechanism  1  has a noise generating device  20  generating 110 db. The measured decibel level on the opposite side of the wall is 40 db. The transmission loss of the wall is 70 db. The transmission loss of, for example, an opening, such as for example, for an electrical socket on the wall can also be determined in a similar manner. The opening  14  of the sound focusing mechanism  1  is located on top of the electrical socket, the decibel level on the opposite side of the wall is then determined using the decibel meter. For example, using the same sound focusing mechanism  1  generating 110 db, the measured decibel level on the opposite side of the wall behind the socket is 51 db. The transmission loss of the socket is 59 db. When this transmission loss of the socket is compared to the other portions of the wall, it can be seen that additional sound proofing measures, such as acoustically wrapping, are needed for the socket in order to reach the same transmission loss as the wall. This is especially useful because it is possible to accurately determine the proper thickness and necessary STC rating of a material to improve the transmission loss. As such, it is possible to propose measures for improving transmission loss that are not in excess of desired levels, which can reduce the costs associated with sound proofing. The above described process can be repeated for almost any object located in a wall, ceiling, floor, etc. 
     The sound focusing mechanism  1  can also be used to determine the overall acoustic path of an object (e.g., a room). The sound focusing mechanism  1  can be located in the center of a room and activated such that a high decibel sound is produced. The decibel meter can then be located in an adjacent room. The decibel level is then recorded. The decibel meter is then positioned at various points in the room such as the walls, the floor and the ceiling. The decibel level is then recorded in the adjacent room with the sound mechanism  1  positioned at each of these locations. By comparing these values with the measured value in the center of the room, it is possible to determine the area, surface or surfaces with the weakest transmission loss. The comparative readings give an estimate of the acoustic path of the sound from one room to another. With these readings it is possible to propose measures for improving transmission loss. For example, based upon the comparative readings, it may be desirable to add a layer of sound insulation to the floor or the ceiling. 
     The operation of the sound focusing mechanism  1  in connection with the determination of the acoustic leakage points of an object will now be described in greater detail. The method of operating the sound focusing mechanism  1  to determine acoustic leakage points will be described in connection with the testing of a pipe. The method is not intended to be so limited. The method and sound focusing mechanism  1  may be used on any object or structure where is it possible that localized acoustic leakage paths exist. For example, the method can be used to locate breaks in sound insulation in a wall or ceiling or floor or pipe wrapping. 
     Often pipes are acoustically wrapped in order to prohibit the sound of running water to be heard. It is difficult after an installation to determine if the acoustic pipe wrapping was completed so that the running water noise will now be inaudible. The opening  14  of the sound focusing mechanism  1  may be located on top of a pipe end or drain. The mechanism  1  is then operated. The high decibel sound is then directed through the pipe. The housing  12  permits the sound to be substantially localized into the pipe so that the user can determine any acoustic leakage. If the acoustic pipe wrapping installation was completed properly, the sound generated by the mechanism  1  will be barely audible. If there is a location in the wrapping where the seal is not complete, then the noise will be very audible. By taking the decibel meter and slowly moving it along the pipe wrapping, the decibel meter will peak at the location where there is an acoustic leakage. 
     It will be appreciated that numerous modifications to and departures from the preferred embodiments described above will occur to those having skill in the art. It is often difficult to allow a person to understand just how much noise a material can stop. For example, the sound focusing mechanism  1  described above can be used to illustrate the STC rating of a particular material. This is especially useful when the acoustic installer is demonstrating the high STC rating of a particular material to a prospective client. A simple illustration can be performed using the mechanism  1 . The mechanism  1  can be positioned against the floor and activated such that the persons in the vicinity can see how much a high decibel sound is reduced, or a good demonstration of the amount of transmission loss is provided by the material forming the container  10 . The mechanism  1  can then be lifted off the floor so that those in the vicinity can hear the difference. Thus, it is intended that the present invention covers the modifications and variations of the invention, provided they come within the scope of the appended claims and their equivalents.