Why powertrain sound matters
Powertrain sound is one of the primary factors in perception of overall vehicle quality. It's also an important emotional element of the driving experience.
Traditional noise and sound control methods used by vehicle engineers can result in significant compromises affecting weight, efficiency, performance, complexity and cost. Bose® Active Sound Management (ASM) Technology offers an alternative approach that lets automakers design and build more efficient, higher performing vehicles—without compromising on desirable sound characteristics.
Bose ASM systems provide solutions for diverse automotive sound engineering challenges. And Bose system engineers bring unrivaled experience in both vehicle acoustics (how sound behaves in the car) and psychoacoustics (how the human ear perceives sound). Our engineers work closely with each automaker's program team to design a system to meet vehicle-specific targets, while reducing development time and costs.
A full-service, tier-one automotive partner
Bose is a tier-one automotive supplier that offers a full service approach to working with OEMs:
- Software: Bose proprietary algorithms—high performance, quality and stability
- Hardware: DSP electronics, transducers and microphones
- Integration: Extensive systems integration expertise and a global presence
- Expert service: Providing expertise in vehicle acoustics and human psychoacoustics, consultation on data analysis, system integration, tuning and equalization
Proprietary software tools: a new standard of speed, control and flexibility
Bose created a suite of software tools specifically for analyzing the sonic environment inside vehicles. These tools, installed on laptop or tablet computers, provide a new level of speed, control and flexibility for evaluating powertrain sound changes—in the vehicle, in real time.
Testing and refining even basic powertrain sound adjustments using traditional simulation methods coupled with mechanical part prototyping can take days and weeks. With Bose proprietary software tools, engineers can make real-time dynamometer and on-track adjustments, and evaluate changes in hours and minutes.
Active Sound Management: different technologies to meet different challenges
Cancel undesirable noise
Bose Engine Harmonic Cancellation (EHC) uses information from the engine along with microphones in the cabin to continuously analyze engine noise. The system then uses the vehicle's audio system to produce a signal acoustically opposite to the undesirable sound and effectively reduce it. EHC allows for a high level of customization and control for the NVH engineer, while providing effective and efficient noise cancellation.
Provide desirable, linear sound
Bose Engine Harmonic Enhancement (EHE) also works with the vehicle's audio system. Using information from the engine and vehicle, it generates a complementary signal to enhance or modify the spectrum of select powertrain sounds, to provide refined and desirable—smooth or sporty—powertrain sound inside the cabin. EHE can help create more linear sound while mitigating or masking sound anomalies. It offers broader sound control than traditional methods and enables more precise control.
Control for multiple modes
Rapid Mode Transition (RMT) module is an optional, add-on feature for Bose EHC or EHE that provides additional capabilities for managing complex noise challenges associated with variable powertrain and cabin modes. When multiple tuning modes are required to achieve a desired powertrain sound character (cylinder deactivation/reactivation, hybrid operation, etc.), the transitions between modes may require special control. The Bose RMT module offers additional control parameters to the engineer for a more seamless sound experience.
For more information about Bose Active Sound Management technology:
Read the article "Active methods for unrestricted sound design", which appeared in ATZ 3/2014.
Download a technical paper.
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