REVIEWS OF ACOUSTICAL PATENTS Free

• GEORGE L. AUGSPURGER, Perception, Incorporated, Box 39 536 Los Angeles, California 90039

• JAMES DEGRANDIS, Acoustics First Corp., 2247 Tomlin Street, Richmond, Virginia 23230

• ERIC E. UNGAR, Acentech, Incorporated, 33 Moulton Street, Cambridge, Massachusetts 02138

Douglas Peter Magyari

11 August 2020; filed 17 January 2018

Figure 1 shows a cross section of an embodiment of the system addressed in this patent, illustrating a series of absorber “cup assemblies” 12 and acoustic cavities 10. Each cup assembly consists of a series of nested components, as shown in the exploded isometric view of Fig. 3, with a typical such component being closed at its bottom and having multiple holes along the flutes of its side walls.—EEU

Michael G. Linihan et al., assignors to EALNILAM, INC.

18 August 2020; filed 5 October 2017

Many people have seen the demonstration of a Chladni plate, though some may not know the name. This is when you have a vibrating plate with a granular material on top, and the antinodes push the grains to settle into the nodes of the plate at that frequency. While the grains show a map of the nodes in the material, they are providing little other value. One group decided that they wanted to capture those patterns and form them into structural elements with strength and stiffness. This capture can be done with a “pickup” sheet, on which the granules are held in place until heated; sintering, melting, or fusing the node pattern into a solid shape. You can then sandwich them between layers of structural material providing a reinforced sublayer within the lamination that can be used to specifically adjust the rigidity of the lamination along the nodal lines. One of the material laminations they propose is to laminate the skeleton into a matrix of carbon fiber; another is using a glass fiber. They also discuss making molds from the skeleton to be able to reproduce the nodal line pattern. This patent specifically covers this method of capturing these nodal structures and not the application or use of those structures as they are a natural phenomenon.—JD

Itzhak Shriki et al., assignors to Itzhak, Shriki

18 August 2020; filed 9 August 2017

Guitars and other stringed instruments require frequent tuning, sometimes during a performance. Small, hand-held digital tuning devices can speed up the process but may be awkward to manipulate. This patent tells us that clamp-on tuning devices are also available, but are unsightly if left in place while performing. The device described in the patent is intended to be small and inconspicuous. The tuning display 118c is positioned to provide good visibility during the tuning process.—GLA

James J. Fallon

18 August 2020; filed 21 May 2018

The loudspeaker used with an electric guitar is sometimes overdriven deliberately to achieve a desired effect. During a professional recording session, the speaker and its pickup microphone are placed inside a closet, or “chimney,” to isolate the guitar from other instruments in the studio. However, when the guitarist works at home, very high sound levels can be annoying to neighbors and dangerous for the musician. This patent describes a special soundproof box that contains an unbaffled loudspeaker 250 and one or more microphones 220, 222. To further reduce the sound level, the air inside the box is partially evacuated when the system is in use. In theory, it should work—the mechanical behavior of a typical guitar speaker is almost independent of the air load. However, a practical implementation may not be all that easy.—GLA

Armin Prommersberger and Matthias von Saint-George, assignors to Harman Becker Automotive Systems GmbH

18 August 2020; filed 5 February 2018

In this automobile sound system, powered loudspeaker 108 and subwoofer 114 are easily removable. They can be replaced by newer models or used outside the auto as components of a portable sound system. Audio feeds to various speakers in the auto are automatically rerouted when one of the speakers is removed from its docking station. Although the flexibility might be convenient, it would also be an invitation for theft.—GLA

Kwan K. Truong et al., assignors to Polycom, Inc.

18 August 2020; filed 20 December 2019

This is the latest in a series of Polycom patents concerned with telephone communication in an open-plan office. The basic setup uses perimeter microphones around designated areas to pick up ambient noise. The noise signals are then processed and used for active noise reduction in the outgoing speech signal.—GLA

Cristian Marius Hera and Ben J. Feng, assignors to Bose Corporation

25 August 2020; filed 18 October 2018

In vehicles with continuously variable transmission, sound from the engine does not correspond to the vehicle's acceleration, thus potentially confusing the vehicle's operator. This patent addresses a means for providing sound feedback to the operator. A virtual gear ratio is calculated, as well as a virtual engine revolutions per minute (rpm), and this information is used to generate an appropriate sound via a loudspeaker.—EEU

Bosco Kante and Maya Kante, assignors to ElectroSpit

25 August 2020; filed 8 November 2018

An “electrolarynx” described in this patent is a hands-free sound modulation device that may be used, for example, by musicians to modify the sound from a keyboard. Such a device consists of a neckband that incorporates sensors that rest against the user's larynx. As the larynx moves, signals from these sensors are processed to provide the desired effect.—EEU

James Thomas O'Keeffe

25 August 2020; filed 28 September 2018

Smartphones are controlled by touchscreens. This smart speaker is controlled by a touch grille. That is right—all 27 patent claims can be condensed into nine words: a sound generating device controlled by a touch grille.—GLA

Rajiv Bernard Gomes et al., assignors to GOOGLE LLC

25 August 2020; filed 22 November 2019

This thin audio actuator is intended to drive the display or casing of a small portable device. Almost everything about the design appears to be familiar prior art except for the mounting struts 302. To reduce depth, these are rabbeted into back plate 304.—GLA

Friedrich Reining et al., assignors to Sound Solutions International Company, Ltd.

25 August 2020; filed 19 September 2019

The force factor of a moving coil loudspeaker (newtons per ampere) is an important parameter. The force factor is usually derived from dynamic measurements, but it can be measured directly with a fairly simple test jig. The method proposed in this patent drives the voice coil with a brief rectangular pulse—less than a millisecond. At the end of the pulse, the driving source is disconnected and the movement of the cone is tracked by a laser or some other sensor. The patent explains how the driving force can then be calculated. The patent also discloses a suitable apparatus for performing the test, including an embodiment for dual voice coil speakers.—GLA

Stefan Keilwert et al., assignors to IGT

1 September 2020; filed 2 August 2018

Electronic gaming machines are usually lined up side-by-side, making it difficult to control sound leakage between adjacent machines. A highly directional loudspeaker or loudspeaker array is required, but it is then easy for a player's head to move outside the beam. Prior art includes at least one patent in which a head tracking device is used to aim a pair of beams at the player's ears. That is the basic approach taken here, but the directional beams are generated by pure wishful thinking. Loudspeaker groups 330, 340 are not used as directional arrays but rather as selectable loudspeakers aimed in different directions. A second embodiment uses a single pair of movable speakers instead. The problem of course is that a small circular diaphragm becomes significantly directional only at frequencies above 2 kHz or so. Over most of the audible range, the directional pattern is a blob, not a beam.—GLA

Masashi Nakamura et al., assignors to TOYOTA JIDOSHA KABUSHIKI KAISHA, DENSO TEN Limited

1 September 2020; filed 20 March 2019

In most automobile sound systems, speakers are mounted on the door panels. The cavity behind a panel serves as the back chamber for the speaker. This kind of installation is simple and inexpensive but speaker performance is degraded by numerous air leaks and strong resonances. It seems obvious that the speaker should have a separate back box, but the available space does not lend itself to a conventional rectangular or cylindrical design. Several patents describe door-mounted back boxes that have unusual shapes and other special features. In the design shown here, the speaker backwave vents into a horizontal tube 2. The tube has absorptive partitions 23 that smooth out internal resonances.—GLA

Abril A. Galang et al., assignors to TOYOTA MOTOR ENGINEERING & MANUFACTURING NORTH AMERICA, INC.

8 September 2020; filed 14 August 2018

Hybrid vehicles employ an internal combustion engine in addition to electric motors. When the engine reaches its maximum rpm as the vehicle accelerates, further speed increases are provided by the electric motors but no increased noise results from the engine, giving the driver an uncomfortable sensation. A control system is used to produce synthetic noise and/or vibration in the vehicle.—EEU

Richard Allen Evans et al., assignors to Cattron North America, Inc.

8 September 2020; filed 29 July 2019

This patent envisions a high-power, ruggedized version of a portable audio player. It is intended to replace the air horn on a diesel locomotive. What is actually patented is an elaborate mounting assembly that is, “…mountable to the handrailing of a locomotive without requiring use of tools.”—GLA

Nikos Zafeiropoulos et al., assignors to Harman Becker Automotive Systems GmbH

8 September 2020; filed 11 July 2019

Harman Becker is doing considerable research into active noise suppression in automobiles. The arrangement described in this patent reduces the computational load by providing a selective active noise cancellation (ANC) system that performs ANC calculations based on desired zones inside the vehicle.—GLA

Sorin V. Dusan et al., assignors to Apple Inc.

8 September 2020; filed 29 September 2017

“Where did I leave my wireless earbuds?” Not to worry: simply ask your smartphone to find them. The smartphone commands the earbuds to play a sine wave at maximum loudness. The acoustic signal is picked up by two or more microphones in the smartphone, and the microphones are configured as a beamformer, allowing the user to zero in on the location of the earbuds.—GLA