Abstract: Furniture such as desks and other items are provided with sound absorbing features consisting of micro-perforations extending through structures having vertical surfaces. The micro-perforations are formed using a LASER cutting tool or a punch and are either cylindrical or frustoconical. The micro-perforations are formed in drawer facings, doors, support structures, and free-standing objects and storage devices having vertical surfaces. The micro-perforations have diameters in the range of 0.20 to 0.70 mm. The micro-perforations have been found to increase sound absorption of a desk by as much as 4 Sabins within the frequency range of 100 to 5,000 Hz. Structural panels consisting of front and rear micro-perforated panels surrounding a porous central core may be employed in such furniture.

Abstract: A plurality of tri-rectangular tetrahedrons are mounted in an array to reflect sound waves back to their source. The array filters out the acoustic range below the normal range of frequencies for the spoken voice. The array is combined with a sound absorber to absorb frequencies the user does not want to have returned to the source. One example of such absorbers consists of rendering the returner somewhat porous with microperforations or microslits so that sound waves below the desired frequency range can travel through the porosity and into an absorbing area which may include fiberglass or other sound absorbing fabrics. Examples of environments of use for the present invention are an office setting or nursing station in which a large room is divided up into spaces or cubicles by partitions. Acoustical returners can be mounted above each space or cubicle, for example, in ceiling mounted arrays or clouds above each space or cubicle.

Abstract: The present invention contemplates regularly spaced or variable width slats having equal width, but with heights determined by an inverted QR sequence, which converts focusing concave areas into beneficial, diffusing convex areas for improved diffusion, especially in the near field. The inverse sequence provides longer resonator necks, between adjacent slats, needed to provide a lower average resonant frequency. Slats are uniformly spaced with inverted QR slat heights have widths determined by the ground states of a Bernesconi sequence. Uniformly spaced, inverted QR slat heights have widths determined by the same QR sequence used to determine heights. Alternatively, uniformly spaced, inverted QR slat heights have widths determined by a Prime 7, primitive root sequence. The uniformly spaced slats have curvilinear forward facing surfaces with their heights based on either a regular or inverted QR sequence, as well as a primitive root or other number theory or optimized sequence.

Abstract: A hexagonal two-dimensional reflection phase grating diffuser includes a plurality of wells that are either part hexagonal or fully hexagonal in cross-section. The depths of the respective wells are determined through calculation of a number theory sequence such as a quadratic residue number theory sequence, a primitive root sequence, or a Chinese remainder theorem. The diffuser may be located within a listening room oriented with openings in the wells facing either downward or horizontally.

Abstract: The present invention contemplates regularly spaced or variable width slats having equal width, but with heights determined by an inverted QR sequence, which converts focusing concave areas into beneficial, diffusing convex areas for improved diffusion, especially in the near field. The inverse sequence provides longer resonator necks, between adjacent slats, needed to provide a lower average resonant frequency. Slats are uniformly spaced with inverted QR slat heights have widths determined by the ground states of a Bernesconi sequence. Uniformly spaced, inverted QR slat heights have widths determined by the same QR sequence used to determine heights. Alternatively, uniformly spaced, inverted QR slat heights have widths determined by a Prime 7, primitive root sequence. The uniformly spaced slats have curvilinear forward facing surfaces with their heights based on either a regular or inverted QR sequence, as well as a primitive root or other number theory or optimized sequence.

Abstract: A hexagonal two-dimensional reflection phase grating diffuser includes a plurality of wells that are either part hexagonal or fully hexagonal in cross-section. The depths of the respective wells are determined through calculation of a number theory sequence such as a quadratic residue number theory sequence, a primitive root sequence, or a Chinese remainder theorem. The diffuser may be located within a listening room oriented with openings in the wells facing either downward or horizontally.

Abstract: An acoustical panel has a multiplicity of short micro-slits, about 10 mm in length each, with each micro-slit having a wedge shaped cross-section in which the opening on the front side of the panel is wider than the opening on the rear side of the panel by a factor of about 2 to effectively absorb sound frequencies in the range of 250-2000 Hz, with the micro-slits greater than 4%. The micro-slits are spaced apart less than 5 mm and several different patterns of micro-slits may be employed including micro-slits that are straight as well as arcuate or some combination of straight and arcuate. The area of the micro-slits on the front surface of the panel exceeds 4%.

Abstract: An acoustical panel has a multiplicity of short micro-slits, about 10 mm in length each, with each micro-slit having a wedge shaped cross-section in which the opening on the front side of the panel is wider than the opening on the rear side of the panel by a factor of about 2 to effectively absorb sound frequencies in the range of 250-2000 Hz, with the micro-slits greater than 4%. The micro-slits are spaced apart less than 5 mm and several different patterns of micro-slits may be employed including micro-slits that are straight as well as arcuate or some combination of straight and arcuate. The area of the micro-slits on the front surface of the panel exceeds 4%.

Abstract: The essence of the present invention is that the thickness of a diffusive fascia of an acoustical treatment is directly correlative of the transition frequency between absorption and pure diffusion. Applicant has found that the thicker the fascia, the lower the transition frequency. For a fascia 600 microns thick, the transition between absorption and diffusion is at about 250 Hz; for a fascia having a thickness of 300 microns, the transition frequency is at about 500 Hz; for a micro-perforated fascia having a thickness of 150 microns, the transition frequency is at about 1,000 Hz; for a fascia having a thickness of 100 microns, the transition frequency is at about 2,000 Hz. An acoustical treatment is created taking these criteria into account. A method of making is also disclosed.

Abstract: Combination light diffusion with either sound diffusion or absorption is provided in a single lighting fixture, to provide uniform luminosity and sound control. The traditional flat light diffuser is replaced with a translucent acoustical element which either diffuses sound or absorbs the sound. The sound diffuser topology includes random surfaces, geometrical shapes, number theoretic diffusers or optimized rectilinear or curvilinear surfaces. The translucent sound absorber includes microperforated or microslit panels, as well as translucent fabrics and microperforated, translucent wood veneers.

Abstract: Combination light diffusion with either sound diffusion or absorption is provided in a single lighting fixture, to provide uniform luminosity and sound control. The traditional flat light diffuser is replaced with a translucent acoustical element which either diffuses sound or absorbs the sound. The sound diffuser topology includes random surfaces, geometrical shapes, number theoretic diffusers or optimized rectilinear or curvilinear surfaces. The translucent sound absorber includes microperforated or microslit panels, as well as translucent fabrics and microperforated, translucent wood veneers.

Abstract: A room acoustic diffuser exploits interference, by reflecting waves out-of-phase with the specular energy, making it possible to diminish specular energy. This is achieved by using a diffuser based on a ternary sequence, which nominally has reflection coefficients of 0, ?1 and +1. A method for obtaining the design sequence for Quaternary diffusers is also disclosed. Also, design methods for forming the sequences into arrays, and forming hemispherical diffusers are explained.

Abstract: An extended bandwidth folded well diffusor extends the diffusion bandwidth of a shallow, asymmetric diffusor by incorporating maximum-depth, folded L-shaped, half-width wells on both ends (sides) of a diffusor, thus providing increased maximum well depth without increasing the physical depth of the diffusor. When the inventive diffusor is placed in an array, the folded L-shaped, maximum-depth, half-width end wells form a novel T-shape, which offers a favorable impedance lowering the resonant frequency, thus extending the diffusor diffusion bandwidth. T-shaped recesses may also be located within a single diffusor. The front surface of the diffusor may be flat or curved or angled.

Abstract: A room acoustic diffuser exploits interference, by reflecting waves out-of-phase with the specular energy, making it possible to diminish specular energy. This is achieved by using a diffuser based on a ternary sequence, which nominally has reflection coefficients of 0, ?1 and +1. A method for obtaining the design sequence for Quaternary diffusers is also disclosed. Also, design methods for forming the sequences into arrays, and forming hemispherical diffusers are explained.

Abstract: An extended bandwidth folded well diffusor extends the diffusion bandwidth of a shallow, asymmetric diffusor by incorporating maximum-depth, folded L-shaped, half-width wells on both ends (sides) of a diffusor, thus providing increased maximum well depth without increasing the physical depth of the diffusor. When the inventive diffusor is placed in an array, the folded L-shaped, maximum-depth, half-width end wells form a novel T-shape, which offers a favorable impedance lowering the resonant frequency, thus extending the diffusor diffusion bandwidth. T-shaped recesses may also be located within a single diffusor. The front surface of the diffusor may be flat or curved or angled.

Abstract: Diverse acoustical modules have identical outward appearance. A series of modules each has an unobtrusive acoustically transparent surface, each module providing a different acoustical functionality while each bears a common outward appearance. Therefore, an acoustical environment can be created specifically suited for the particular application, but devoid of any distracting differences of appearance between the respective absorbers, reflectors, and diffusers that are employed to create the aesthetic appearance. One manner of installation can include a grid structure suspended from the existing ceiling and allowing each module to be removably installed in a space having a desired shape such as a square or rectangle. Alternatively, the different acoustical treatment modules can be directly surface mounted to a ceiling or wall, preferably in a manner permitting easy removal for servicing or replacing due to damage or changing acoustical characteristics.

Abstract: Embodiments of aperiodic tiling of a single asymmetrical diffusive base shape employ welled or stepped one-dimensional or two-dimensional diffusors, a single or compound curved surface, or an aperiodic geometrical form. Surfaces are tiled in any orientation offering an unlimited number of tiling patterns. In the preferred embodiments of the present invention, a smooth transition between adjacent “tiles” is achieved. Using a single tileable asymmetric base shape reduces the number of shapes requiring manufacture while allowing modulation. The present invention even contemplates extending the inventive techniques into three-dimensional shapes to form volume diffusors. The technique employed to design diffusors to be used in accordance with the teachings of the present invention may rely upon visual appearance, a random sequence, a number theory sequence, or use of an optimization program.

Abstract: Embodiments of aperiodic tiling of a single asymmetrical diffusive base shape employ welled or stepped one-dimensional or two-dimensional diffusers, a single or compound curved surface, or an aperiodic geometrical form. Surfaces are tiled in any orientation offering an unlimited number of tiling patterns. In the preferred embodiments of the present invention, a smooth transition between adjacent “tiles” is achieved because the perimeter of each tile, where necessary, is provided with a specific depth and gradient whereby when adjacent tiles are placed in adjacency, there is a smooth transition between the adjacent tiles. Using a single tileable asymmetric base shape reduces the number of shapes requiring manufacture while allowing modulation. The present invention even contemplates extending the techniques thereof into three-dimensional shapes to form volume diffusors.

Abstract: An existing diffuser is modified by creating through-holes in its diffusive surface that allow sound to travel through the diffuser to the rear of it where an absorptive material is provided. The absorptive material may be made of any suitable material such as fiber glass, foam or mineral wool. The cut-off frequency between diffusion and absorption may be “tuned” or adjusted by varying the total volume of holes made within the diffuser, and by determining the particular cavities (and their depths) that are chosen to be modified through the provision of holes. In each embodiment of the present invention, holes or slots are formed in a diffusive surface and such holes or slots form one component of a resonant absorber. The perforations can be any shape or size and by varying the perforation and cavity size, the inventive devices may be “tuned” to begin to absorb sound below a desired chosen frequency.

Abstract: A motorized and computer controlled TRIFFUSOR® acoustical treatment system includes a plurality of TRIFFUSOR® banks mounted in various locations within a listening room. Mechanical actuators such as gears and sprockets are employed to mechanically couple the individual units of each bank together. In the preferred embodiment, an electrical motor is coupled into the gearing so that rotation of the electrical motor results in indexing of the different faces of each TRIFFUSOR® unit to the three possible positions (absorptive, reflective or diffusive) facing the interior of the listening room. A programmable logic-controlled motor control unit is provided and programmed to coordinate activation of different TRIFFUSOR® banks throughout the listening space.