Abstract: Audio systems, methods, and computer readable mediums having program code to receive a harmonic signal related to rotating equipment, such as a vehicle drivetrain in some examples, and provide a harmonic cancellation (or enhancement) signal. The harmonic cancellation signal is transduced into an acoustic signal, and a feedback sensor, such as a microphone, detects an error signal representative of acoustic energy at a first location in the environment. A projection filter filters the error signal to provide an estimated error signal at a second location in the environment, such as at the location of an occupant's ear(s). An adaptive module adjusts the cancellation signal based on the estimated error signal.

Abstract: An acoustic conduit provides a waveguide for coupling a loudspeaker inside a vehicle to a region outside the vehicle, or vice versa. The acoustic conduit includes a proximal opening configured to accommodate the loudspeaker. A distal opening is configured to acoustically couple to an exterior of the vehicle. The acoustic conduit defines an interior volume between the proximal opening and the distal opening and is configured to provide waveguide acoustic coupling between the loudspeaker and the exterior.

Abstract: In a vehicle equipped with a vehicle sound system, determining a virtual fixed gear ratio; determining a virtual RPM based on the virtual fixed gear ratio; generating a set of harmonic signals based on the virtual RPM, the harmonic signals being sine-wave signals proportional to harmonics of the virtual RPM; processing the harmonic signals to produce a set of processed harmonic signals; and in the vehicle sound system, transducing the processed harmonic signals to acoustic energy thereby to produce an engine sound within a passenger cabin of the vehicle.

Abstract: An acoustic conduit provides a waveguide for coupling a loudspeaker inside a vehicle to a region outside the vehicle, or vice versa. The acoustic conduit includes a proximal opening configured to accommodate the loudspeaker. A distal opening is configured to acoustically couple to an exterior of the vehicle. The acoustic conduit defines an interior volume between the proximal opening and the distal opening and is configured to provide waveguide acoustic coupling between the loudspeaker and the exterior.

Abstract: In a vehicle equipped with a vehicle sound system, determining a virtual fixed gear ratio; determining a virtual RPM based on the virtual fixed gear ratio; generating a set of harmonic signals based on the virtual RPM, the harmonic signals being sine-wave signals proportional to harmonics of the virtual RPM; processing the harmonic signals to produce a set of processed harmonic signals; and in the vehicle sound system, transducing the processed harmonic signals to acoustic energy thereby to produce an engine sound within a passenger cabin of the vehicle.

Abstract: In a vehicle equipped with a vehicle sound system, determining a virtual fixed gear ratio; determining a virtual RPM based on the virtual fixed gear ratio; generating a set of harmonic signals based on the virtual RPM, the harmonic signals being sine-wave signals proportional to harmonics of the virtual RPM; processing the harmonic signals to produce a set of processed harmonic signals; and in the vehicle sound system, transducing the processed harmonic signals to acoustic energy thereby to produce an engine sound within a passenger cabin of the vehicle.

Abstract: A method of creating in situ an acoustic enclosure in a space that is between body panels of a motor vehicle, wherein the space defines an empty volume, the method comprising placing into the space between body panels a molding tool that comprises a solid barrier that divides the space between body panels into an interior portion on an inside of the molding tool and an exterior portion that is external to an outside of the molding tool, where the outside of the molding tool is exposed to the space between body panels, and while the molding tool is in the space between the panels, introducing a fluid material into the exterior portion of the space between the body panels, wherein the fluid material is configured to cure into a solid shell.

Abstract: A method to produce a dynamic sound stage for engine harmonic enhancement (EHE). Dynamic refers to the ability to position the sound stage at different positions as the engine operates at various RPMs and load. In order to control the sound stage width, a phase difference can be introduced between a first audio channel (e.g., a left audio channel) and second audio channel (e.g., a right audio channel). In the most general case, the phase difference can be introduced per harmonic per RPM. In this approach, the phase difference can be adjusted such that a vehicle occupant will perceive each harmonic signal to have a particular width. This width can be adjusted independently per RPM regions by tuning the per harmonic phase difference.

Abstract: A method to produce a dynamic sound stage for engine harmonic enhancement (EHE). Dynamic refers to the ability to position the sound stage at different positions as the engine operates at various RPMs and load. In order to control the sound stage width, a phase difference can be introduced between a first audio channel (e.g., a left audio channel) and second audio channel (e.g., a right audio channel). In the most general case, the phase difference can be introduced per harmonic per RPM. In this approach, the phase difference can be adjusted such that a vehicle occupant will perceive each harmonic signal to have a particular width. This width can be adjusted independently per RPM regions by tuning the per harmonic phase difference.

Abstract: A method of creating in situ an acoustic enclosure in a space that is between body panels of a motor vehicle, wherein the space defines an empty volume, the method comprising placing into the space between body panels a molding tool that comprises a solid barrier that divides the space between body panels into an interior portion on an inside of the molding tool and an exterior portion that is external to an outside of the molding tool, where the outside of the molding tool is exposed to the space between body panels, and while the molding tool is in the space between the panels, introducing a fluid material into the exterior portion of the space between the body panels, wherein the fluid material is configured to cure into a solid shell.

Abstract: A method to produce a dynamic sound stage for engine harmonic enhancement (EHE). Dynamic refers to the ability to position the sound stage at different positions as the engine operates at various RPMs and load. In order to control the sound stage width, a phase difference can be introduced between a first audio channel (e.g., a left audio channel) and second audio channel (e.g., a right audio channel). In the most general case, the phase difference can be introduced per harmonic per RPM. In this approach, the phase difference can be adjusted such that a vehicle occupant will perceive each harmonic signal to have a particular width. This width can be adjusted independently per RPM regions by tuning the per harmonic phase difference.

Abstract: In a vehicle equipped with a vehicle sound system, determining a virtual fixed gear ratio; determining a virtual RPM based on the virtual fixed gear ratio; generating a set of harmonic signals based on the virtual RPM, the harmonic signals being sine-wave signals proportional to harmonics of the virtual RPM; processing the harmonic signals to produce a set of processed harmonic signals; and in the vehicle sound system, transducing the processed harmonic signals to acoustic energy thereby to produce an engine sound within a passenger cabin of the vehicle.

Abstract: In a vehicle equipped with a vehicle sound system, determining a virtual fixed gear ratio; determining a virtual RPM based on the virtual fixed gear ratio; generating a set of harmonic signals based on the virtual RPM, the harmonic signals being sine-wave signals proportional to harmonics of the virtual RPM; processing the harmonic signals to produce a set of processed harmonic signals; and in the vehicle sound system, transducing the processed harmonic signals to acoustic energy thereby to produce an engine sound within a passenger cabin of the vehicle.

Abstract: A method to produce a dynamic sound stage for engine harmonic enhancement (EHE). Dynamic refers to the ability to position the sound stage at different positions as the engine operates at various RPMs and load. In order to control the sound stage width, a phase difference can be introduced between a first audio channel (e.g., a left audio channel) and second audio channel (e.g., a right audio channel). In the most general case, the phase difference can be introduced per harmonic per RPM. In this approach, the phase difference can be adjusted such that a vehicle occupant will perceive each harmonic signal to have a particular width. This width can be adjusted independently per RPM regions by tuning the per harmonic phase difference.

Abstract: In a vehicle equipped with a vehicle sound system, determining a virtual fixed gear ratio; determining a virtual RPM based on the virtual fixed gear ratio; generating a set of harmonic signals based on the virtual RPM, the harmonic signals being sine-wave signals proportional to harmonics of the virtual RPM; processing the harmonic signals to produce a set of processed harmonic signals; and in the vehicle sound system, transducing the processed harmonic signals to acoustic energy thereby to produce an engine sound within a passenger cabin of the vehicle.