This invention relates to sound systems and, in particular, to sound masking systems for offices, e.g., open plan offices.
Freedom from distraction is an important consideration for workers' satisfaction with their office environment, and, in order to reduce the intelligibility of unwanted speech overheard in various office configurations, sound masking systems have been used. However, there is an ongoing need to improve the ease of installation, aesthetic appearance, power requirements, cost, effectiveness and/or other characteristics of sound masking systems.
In accordance with an embodiment of the invention, there is provided a sound vibration excitation assembly for producing direct field sound masking, paging and/or music. The assembly comprises a ceiling coupler configured to be coupled to a single contact area on a discrete area sound-absorbing ceiling surface, such as an acoustical ceiling tile or cloud, comprising, e.g, mineral fiber or fiberglass, and a vibration exciter that is configured to be electrically coupled to one or more sources of an electrical sound signal and is coupled to the ceiling coupler to produce vibrations in the ceiling coupler in response to the electrical sound signal.
In further, related embodiments, the electrical sound signal may comprise a sound masking signal and/or at least one of a music signal and a paging signal. The ceiling coupler may comprise an attachment plate. The attachment plate may comprise a bottom surface configured to conform to and to be attached face to face to a surface of the discrete area sound absorbing ceiling surface. The bottom surface of the attachment plate may be, e.g., substantially flat, concave or convex, or undulating. The sound vibration excitation assembly may further comprise an adhesive layer on the bottom surface of the attachment plate, and a removable backing paper overlaying a bottom surface of the adhesive layer. In projection on to a flat surface, the attachment plate may comprise a continuously curved plate or a polygonal plate, such as a triangular plate. In another embodiment, the ceiling coupler may comprise a recess attachment piece configured to be positioned in a recess in a top surface of the discrete area sound absorbing ceiling surface. The recess attachment piece may comprise at least one spring-loaded fitting configured to penetrate the discrete area sound absorbing ceiling surface. In another embodiment, the ceiling coupler may comprise an attachment piece configured to be embedded inside the discrete area sound absorbing ceiling surface. The ceiling coupler may comprise a metal, such as steel or aluminum, and/or a plastic, such as at least one of poly(methyl methacrylate) and polycarbonate. The ceiling coupler may, but is not required to, comprise a substantially larger minimum dimension than a maximum dimension of the vibration exciter. The vibration exciter may comprise a voice coil, a piezoelectric element (such as a piezoelectric bender bar) or a single-ended electrostatic element. The vibration exciter may be mounted directly to the ceiling coupler.
In further, related embodiments, the discrete area sound-absorbing ceiling surface may comprise a mineral fiber ceiling tile. The sound vibration excitation assembly may further comprise a quick connect/disconnect jack electrically coupled to the vibration exciter. The quick connect/disconnect jack may correspond to a TIA/EIA-IS-968-A Registered Jack 45 (RJ-45) connector. The vibration exciter may be coupled to the ceiling coupler to produce vibrations in the discrete area sound-absorbing ceiling surface to thereby emit an acoustic sound signal in response to the electrical sound signal. When the electrical sound signal is a sound masking signal capable of causing the vibration excitation assembly to produce vibrations in the discrete area sound-absorbing ceiling surface, an acoustic sound masking signal is emitted, where the acoustic sound masking signal has a corresponding sound masking spectrum suitable for sound masking as is well known by those of skill in the art. The low end frequencies preferably comprise at least one of 50 Hz, 80 Hz and 100 Hz, most preferably 80 Hz. The high end frequencies are preferably less than 8 kHz and more preferably about 5300 Hz or less. The assembly may further comprise the one or more sources of the electrical sound signal attached to the ceiling coupler and electrically coupled to the vibration exciter. The assembly may further comprise an input network electrically coupled to the vibration exciter. The vibration exciter may be further electrically coupled to receive a Direct Current (DC) electrical current in addition to the electrical sound signal. The vibration exciter may, preferably, comprise a voice coil of a rating less than or equal to a 5 pound force.
The sound vibration excitation assembly may further comprise a cone loudspeaker assembly and a crossover circuit electrically coupled to the cone loudspeaker assembly and to a vibration exciter, where the crossover circuit is configured: (i) to operatively couple the one or more sources of the electrical sound signal to the vibration exciter to produce output of an acoustic sound signal from the discrete area sound-absorbing ceiling surface in a range of frequencies lower than a threshold frequency, and (ii) to operatively couple the one or more sources of the electrical sound signal to the cone loudspeaker assembly to produce output of the acoustic sound signal from the cone loudspeaker assembly in a range of frequencies higher than the threshold frequency.
In another embodiment according to the invention, there is provided a sound system, the system comprising: a discrete area sound-absorbing ceiling surface comprising mineral fiber or fiberglass; and any of the sound vibration excitation assemblies taught herein, the ceiling coupler being coupled to the single contact area on the discrete area sound-absorbing ceiling surface; wherein the vibration exciter of the sound assembly is coupled to the ceiling coupler to produce vibrations in the ceiling coupler in response to an electrical sound signal.
In further, related embodiments, the discrete area sound-absorbing ceiling surface may comprise a mixture comprising: mineral fibers, perlite, cellulosic fibers and a binder. The discrete area sound-absorbing ceiling surface may comprise a substantially uniform density mineral fiber core. The system may further comprise at least a top skin and a bottom skin of the discrete area sound-absorbing ceiling surface. The discrete area sound-absorbing ceiling surface may comprise a synthetic mineral wool, recycled paper and/or cloth. The discrete area sound-absorbing ceiling surface may be sized to fit within a suspended ceiling grid of multiple such discrete area sound-absorbing ceiling surfaces. The suspended ceiling grid may comprise a size of at least one of: one foot by one foot, two feet by two feet, and two feet by four feet. The discrete area sound-absorbing ceiling surface may be configured in at least one of: an arch shape, at least a portion of a cloud array of mineral fiber or fiberglass surfaces, a polygonal shape, an oval shape, and a circle shape. The ceiling coupler may be coupled to an upper surface of the discrete area sound-absorbing ceiling surface, wherein the discrete area sound-absorbing ceiling surface comprises no sound components protruding through or below its bottom surface. The discrete area sound-absorbing ceiling surface may comprise a pre-existing discrete area sound-absorbing ceiling surface in an area of a building comprising, e.g., a sound masking zone below the discrete area sound-absorbing ceiling surface, the pre-existing discrete area sound-absorbing ceiling surface having been otherwise unmodified for sound masking other than by coupling of the sound assembly to the surface of the discrete area sound-absorbing ceiling surface. The sound system may further comprise a cone loudspeaker assembly coupled to the discrete area sound-absorbing ceiling surface.
In another embodiment according to the invention, there is provided a method of performing sound masking. The method comprises supplying an electrical sound masking signal to a sound masking assembly, such as any of the sound masking assemblies taught herein, the sound masking assembly being coupled to a discrete area sound-absorbing ceiling surface, such as any such surfaces taught herein, to thereby cause the sound masking assembly to produce vibrations in the discrete area sound-absorbing ceiling surface in response to the electrical sound masking signal, and thereby emitting an acoustic sound masking signal.
In another embodiment according to the invention, there is provided a method of installing a sound masking system. The method comprises, prior to mounting the sound masking system to a discrete area sound-absorbing ceiling surface, electrically coupling one or more sources of an electrical sound masking signal to any of the sound assemblies taught herein. The method further comprises subsequently attaching the ceiling coupler of the sound assembly to an upper surface of the discrete area sound-absorbing ceiling surface to mount the sound masking system above the discrete area sound-absorbing ceiling surface. The sound masking system can then be operated without ever uncoupling the one or more sources of the electrical sound masking signal from the sound assembly. The method may further comprise installing in a similar fashion any of the sound systems taught herein.
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.
A description of example embodiments of the invention follows.
In accordance with an embodiment of the invention, there is provided a sound vibration excitation assembly that can be installed on a surface of a discrete area sound-absorbing ceiling surface, for example an ordinary, commercially sold mineral fiber ceiling tile, either pre- or post-installation. The sound assembly permits the discrete area sound-absorbing ceiling surface to be used, for example, to produce a sound masking signal for performing sound masking in a predetermined area below the sound-absorbing ceiling surface, and may also be used for emitting other sounds into the area, such as music and paging sound. The sound assembly provides an aesthetically unobtrusive sound system, and may permit more convenient installation of the sound system compared to other such systems. Further advantages of embodiments according to the invention are discussed below.
In accordance with an embodiment of the invention, a ceiling coupler, such as attachment plate 102, may be configured to be coupled to a single contact area 216 on the discrete area sound-absorbing ceiling surface 209, as shown in
In the embodiments of
In accordance with an embodiment of the invention, the strength properties, such as the hardness, friability, sag and/or transverse strength, of the discrete area sound-absorbing ceiling surface may be measured and characterized according to the standards set forth in ASTM Standard C367/C367M, entitled “Standard Test Methods for Strength Properties of Prefabricated Architectural Acoustical Tile or Lay-In Ceiling Panels,” published by ASTM International of West Conshohocken, Pa., U.S.A., the entire disclosure of which is hereby incorporated herein by reference.
Further, in accordance with an embodiment of the invention, the acoustical ratings of the discrete area sound-absorbing ceiling surface may be measured and characterized according to the standards set forth in ASTM Standard E1264, entitled “Standard Classification for Acoustical Ceiling Products,” published by ASTM International of West Conshohocken, Pa., U.S.A., the entire disclosure of which is hereby incorporated herein by reference.
In addition, the discrete area sound-absorbing ceiling surface in accordance with an embodiment of the invention need not be in the shape of a tile; for example, the discrete area sound-absorbing ceiling surface can be an arch shape, a polygonal shape, an oval shape, a circle shape, or another shape. Such shapes may, for example, be made of mineral fiber and pre-cut into such shapes. In addition, the discrete area sound-absorbing ceiling surface may be at least a portion of a “cloud” array of ceiling surfaces. For example, a cloud array is often formed of multiple mineral fiber surfaces arranged in an array that is suspended above a floor area in a building, and, in accordance with an embodiment of the invention, may have a sound assembly taught herein attached to at least one surface in the cloud array. For example, a sound assembly taught herein may be used in a six by three mineral fiber cloud array, or another cloud array. The ceiling coupler, such as attachment plate 202 may be of a shape, and may be in a position on the ceiling tile 209, which optimizes the acoustical output as desired, for example for sound masking. The attachment plate 202 or other ceiling coupler may be attached to the ceiling tile 209 using any suitable long-lasting adhesive, such as a spray-on glue or a foam tape. For example, the attachment plate 202 or other ceiling coupler may have double sided foam tape on its bottom surface, such as 3M™ double-coated urethane or polyethylene foam tape sold by 3M Company of St. Paul, Minn., U.S.A.
In accordance with an embodiment of the invention, the vibration exciter 201 may comprise a voice coil, of a type discussed further below, or other types of vibration exciters discussed further below.
In one embodiment according to the invention, the vibration exciter 201 may be electrically coupled to receive a Direct Current (DC) electrical current in addition to the electrical sound signal. This may be useful in order to prevent the weight of the vibration exciter 201, for example when the vibration exciter 201 is a voice coil assembly, from reducing the possible amplitude of vibration because of a gravitationally induced offset, since the DC current will function to lift the magnet back to a neutral position that is in a direction away from the discrete area sound-absorbing ceiling surface 209, thereby counteracting the weight of the voice coil. Alternatively, or in addition, a mechanical support structure of the vibration exciter 201 may be strengthened.
With reference to the embodiment of
By virtue of using such a sound assembly attached to the discrete area sound-absorbing ceiling surface 209, a system in accordance with an embodiment of the invention may provide the advantage of permitting the lowest frequency components of the sound signal to be lower than would ordinarily be the case with some cone loudspeakers. Further, the sound system may be entirely hidden from a viewer, by virtue of being concealed above the discrete area sound-absorbing ceiling surface 209, and may preclude the listener from locating the sound system. The system may also be more convenient and inexpensive to install than other tile mounted sound masking systems, since no modification of the ceiling is required. For example, the discrete area sound-absorbing ceiling surface 209 may be a pre-existing ceiling tile in an area of a building comprising a sound masking zone below the ceiling tile; and the attachment plate 202 or other ceiling coupler may be directly attached to a top surface of the ceiling tile, where the pre-existing ceiling tile is otherwise unmodified for sound masking. As another advantage, the sound assembly according to the invention may provide a slightly larger area of coverage per sound assembly than conventional cone loudspeakers, because the attached discrete area sound-absorbing ceiling surface (such as a mineral fiber ceiling tile) may radiate the produced acoustic sound signal over a larger area into the space below the ceiling surface compared to that possible with conventional systems. In addition, while not being bound by any theory, it appears that a mineral fiber ceiling tile, for example, performs well in producing a diffuse and incoherent masking sound, by virtue of exciting a variety of different modes of vibration of the mineral fiber ceiling tile.
A sound masking system in accordance with an embodiment of the invention may use a sound masking spectrum based on the principles of the spectrum described in L. L. Beranek, “Sound and Vibration Control,” McGraw-Hill, 1971, Page 593, the teachings of which reference are incorporated by reference in their entirety. The low end frequencies of the selected spectrum preferably comprise at least one of 50 Hz, 80 Hz and 100 Hz, most preferably 80 Hz. The high end frequencies are preferably less than 8 kHz and more preferably about 5300 Hz or less. It will be appreciated that other sound masking spectra may be used.
In the embodiment of
In addition, other types of vibration exciters may be used that are not voice coils. For example, the vibration exciter may comprise a piezoelectric element (such as a piezoelectric bender bar) or a single-ended electrostatic element. More than one exciter, and more than one different type of exciter, may be used in one assembly. The vibration exciter may be mounted directly to the ceiling coupler, for example by adhering a voice coil (or other vibration exciter) directly to the attachment plate (or other ceiling coupler), without an intervening support structure other than any small supports that are conventionally included to support a voice coil.
In accordance with an embodiment of the invention, a discrete area sound-absorbing ceiling surface 209 (see
A sound system in accordance with an embodiment of the invention may be used to output other sounds, in addition to sound masking signals, such as for music and paging, using the vibrations of the same discrete area sound-absorbing ceiling surface 209 that is used for sound masking.
Further, a sound system in accordance with an embodiment of the invention may be used in conjunction with known features of sound masking systems generally, such as those taught in U.S. Pat. No. 7,194,094 B2 of Horrall et al., the teachings of which patent are incorporated by reference in their entirety.
The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.
While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
This application claims the benefit of U.S. Provisional Application No. 62/065,492, filed on Oct. 17, 2014, the entire teachings of which application are incorporated herein by reference.
Number | Date | Country | |
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62065492 | Oct 2014 | US |