Virtually Tuning an Automotive Audio System

Engineers at HARMAN are using numerical simulation to improve the development process for the latest vehicle infotainment technology.

The following is an excerpt from Multiphysics Simulation 2016.

Today’s vehicles offer dazzling electronic entertainment possibilities, from smartphone connectivity to interactive displays and video screens. HARMAN is the market leader in these connected car setups, equipping more than 80% of the world’s luxury cars with premium audio systems.

Each vehicle model requires a unique configuration, and HARMAN’s team of acoustic and simulation specialists ensure that different components and car acoustics are accounted for in their design process. Details such as the ideal placement and orientation of speakers, speaker packaging, and driver enclosure geometry such as car doors all influence the sound quality.

The team uses physical experiments in conjunction with numerical analysis to accelerate product development by virtually “tuning” their systems before ever creating a live prototype. This saves time on physical testing, and allows virtual tests to replace in situ listening, so that the team can design their products even before the final car designs are complete.

“We may become involved very early in the car development process, when a vehicle designer has not yet decided what is required from the audio system,” explains Michael Strauss, Senior Manager of Virtual Product Development and Tools (VPD) at HARMAN. “Or we may only have basic details such as size and volume of the car cabin. Yet frequently we need to present a concept within a few days, creating a tricky challenge to meet our clients’ requirements and deliver high-quality systems.”

Simulation and Experiments Team Up for Customer Satisfaction

To provide customers with a response that is both quick and accurate, engineers at HARMAN turn to mathematical modeling in COMSOL Multiphysics® software. “We needed capabilities for mechanical, acoustic, and electrical simulations in one integrated environment, and we wanted a program that would free up the time and effort spent on creating and updating our own tools,” says François Malbos, Principal Acoustics Engineer, at HARMAN.

“The multiphysics approach is one of the most important parts of the virtual product development process,” says Michał Bogdański, Simulation Engineer and Leader of the Project at HARMAN. “We can explore how the acoustic behavior of a loudspeaker relates to any part of a vehicle structure — for example the stiffness of a door — and then provide door design guidelines to our customer.”

In one case, they both measured and simulated the sound pressure levels generated by a loudspeaker in the cabin of a Mercedes-Benz ML car (Figure 1) in order to validate their numerical models and later use them to optimize acoustic equipment. “Car cabin simulations are among the most challenging to run because they cover many different areas of physics,” explains Strauss. Fortunately, COMSOL® software offers options to couple together the acoustic, mechanical, and electrical effects throughout the system. [READ MORE]