The first Bose Active Sound Management (ASM) systems have entered production vehicles in 2011 after about five years of development utilizing extensive experience in audio signal processing and vehicle acoustics. This paper illustrates the functionality and use cases of Bose ASM systems. The major Bose ASM algorithms, Engine Harmonic Cancellation (EHC) and Engine Harmonic Enhancement (EHE) provide OEMs with precise control of in-cabin engine sound by treating each harmonic as a function of various vehicle control inputs. The technology can replace passive acoustic materials or devices saving their mass, package space and development cost. Changes to the vehicle's acoustics can be implemented without costly hardware re-designs. The systems are designed to be tolerant towards production and lifetime variation. Stable, inconspicuous operation has been proven in several production vehicles on the market. The active, closed-loop EHC algorithm uses microphones and the infotainment system's speakers to reduce unwanted engine orders. The algorithm has capabilities to adapt to varying acoustics of the vehicle interior while maximizing cancellation. It also offers comprehensive instability countermeasures to prevent malfunction against large transfer function variations. The EHE algorithm offers capability to add multiple engine orders through the car's speakers to reproduce a settable target sound depending on a wide range of vehicle control inputs including RPM, engine load, accelerator pedal position and current gear. The enhancement signal utilizes know-how from premium audio systems to provide natural sound and prevent localization of the speakers even at high levels of enhancement. The enhancement signal can be panned (e.g. to the front or rear) for individual orders by using a variety of spatial control techniques. Main points: (1) Bose ASM is mass-market applicable, (2) Algorithms provide precise control of in-cabin engine sound, (3) Ability to reduce or enhance engine harmonics selectively, (4) Stable performance under all conditions, (5) Powerful NVH tool to tackle various problems without heavy expensive hardware, (6) Enables short-term engine sound tuning until late in the engine / vehicle development cycle Innovative value. While the concept of actively controlling in-car engine sound through speakers has evolved over decades, this paper presents the capabilities, challenges and use cases of one of the first mass market applicable approaches. Bose ASM provides NVH (noise, vibration, and harshness) engineers with a tool to reduce or enhance engine orders precisely and individually as functions of RPM and other engine control signals in ranges of more than ±15 dB. The approach exploits Bose know-how from premium sound systems to provide natural sound and spatial control and to prevent speaker localization. Mass-market applicability also implies potent countermeasures against instability risks inherent in closed loop systems and variations in vehicle transfer functions due to age, production spread or changing vehicle conditions. Use cases include but are not limited to new two or three cylinder engines, turbo charged engines, cylinder deactivation, advanced NVH quality, conditional engine sound strategies and mass / cost savings gained by replacing conventional passive noise mitigation materials or devices. Bose ASM enables dramatic changes in the powertrain / vehicle NVH development process as it can be re-adapted effortlessly at any stage. Consequently, it also increases flexibility towards market trends like fuel economy or certain NVH targets and allows for more precise vehicle positioning in faster evolving development cycles.


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    Title :

    Bose active sound management


    Contributors:
    Ahrens, Simon (author) / Fox, Ulrich (author) / Feng, John (author)


    Publication date :

    2013


    Size :

    22 Seiten, 13 Bilder, 4 Tabellen, 2 Quellen


    Type of media :

    Conference paper


    Type of material :

    Storage medium


    Language :

    English




    Bose Active Sound Management

    Ahrens,S. / Fox,U. / Feng,J. et al. | Automotive engineering | 2013



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