The growing electrification trend in the automotive industry is noticeably reshaping vehicle development. This new power train concept has a direct impact on other vehicle performance aspects and introduces new challenges. One of the main concerns that is even changing the legal framework on the international level is the acoustic characteristics of these vehicles.
This is the moment when the rising technology called ”active sound design” comes into play. This technology generates artificial sound and plays it back through the audio system to improve interior noise. In other words, next to the functional sounds in the car, sound design generates meaningful sounds serving several purposes. On one hand it masks the unpleasant sounds. And on the other hand, it creates acoustic feedback by adding the missing engine orders. On top of that, active sound design generates exterior sound to also serve the original equipment manufacturers’ (OEMs) legal requirement to develop acoustic vehicle alerting systems (AVAS). (For more information check out this white paper.).
Replacing the traditional internal combustion engine (ICE) obviously brings some disadvantages. But interestingly, you can turn these into brand advantages easily when using new acoustic tools. The fact the electrified powertrain has unpleasant high tonal noises, there is no acoustic feedback. Next to that, noises that were previously masked by the loud combustion engine, are now obvious. This makes development teams to seek new tools to ensure appealing sound quality.
What is active sound design about?
Active sound design had already been around for several years. This technology was originally developed for ICE vehicles. When the combustion engine underwent a major transformation caused by cylinder deactivation and OEMs started to build one engine for different product lines (for example, sporty and luxury models), active sound design helped to ensure attractive sound signatures that matched customer expectations. This active sound design is still extensively used in this market segment.
The electrification of the powertrain brings active sound design to the next level. Although artificial sound served mainly the sound quality and emotional considerations in ICE vehicles, sound design becomes functional and an integral aspect of the driving experience in the electrified vehicles. In hybrid vehicles, this technology can acoustically resolve the inconsistent interior scenarios (for example, the moment between the engine switches). For electrical vehicles this solution offers options to create consistent acoustic feedback for the driver, reflecting the engine orders and driving conditions (acceleration, braking, etc.), which is per default absent in electrified engines.
Claim your brand sound signature with active sound design
And what should this sound like? This is the question the acoustic development teams are striving to answer. Adding artificial sound to a vehicle unveils a great branding opportunity, especially for the electrified powertrains, where most engines sound similar and miss the brand identity. Active sound design empowers the OEMs to compose a new sound signature reflecting the company’s legacy. On the one hand, you can adapt active sound design according the driving mode – eco, sport, comfort. On the other hand, this system masks unwanted sounds and increases the cabin sound quality.
This technology has several advantages. Firstly, to ensure appealing sound quality, acting on the acoustic level OEMs can steer away from the strategy of adding damping material or changing the design of systems or components. Both strategies are usually associated with higher cost. And moreover, the result can deteriorate the vehicle economy performance, unlike adding artificial sound that requires only integration of new electronics. Secondly, you can add active sound design later in the development cycle. This allows the development teams to first gain an understanding of how the car behaves and only then do they design the sound accordingly. Sound development is independent of the mechanical development. You can change the sound using the software later without any physical vehicle changes.
Get covered also for the AVAS requirement
As mentioned, active sound design also represents a solution for the recent legal requirement of AVAS in electrified vehicle to achieve minimal noise levels. The same system can emit exterior sounds reflecting the driving conditions to alert other road users. This sound signature should be brand-bounded and easily identifiable.
New tools for new challenges
The expectations for new vehicle sound, either technical or emotional, carry new challenges for the acoustic development teams. Designing new vehicle sound doesn’t only require good technical knowledge, but it also entails expertise from the music world and composition skills. Siemens Digital Industries Software has recently extended the Simcenter™ software portfolio with active sound design solutions engaging music with technical expertise. This correspondent tool chain empowers acoustic engineers to translate driveline condition into artificial sound. The artificial sound can be either order or non-order based. The system has a direct link to the vehicle dynamics as it reads the information from the CAN bus. Applying complex algorithms, it generates sound based on wave tables, frequency modulation, granular synthesis, etc.
This off-the-shelf solution by Siemens Digital Industries Software provides great development flexibility. The acoustic teams need only to create a connection to the CAN bus and vehicle and connect it with dedicated hardware and software. You can use this setup in various environments – in a laboratory, on a simulator or directly in the vehicle. More interestingly, working with this system enables the acoustic engineers to change any parameters in real time with immediate reaction.
Integrated in Simcenter Testlab environment
Being part of the industry-leading noise, vibration and harshness (NVH) platform, such as Simcenter™ Testlab, this solution accommodates direct access to sound quality engineering and an AVAS minimum noise certification framework.
Today, OEMs producing electric cars stand at a crossroads. Will they design completely new, futuristic-sounding acoustic signatures or will they keep the ICE-ish sound? Most likely, we will hear the answer soon. But it is obvious that Simcenter solutions for active sound design offer a comprehensive and flexible toolbox to achieve a chart-topping outcome.
Do you want to learn more about active sound design?
Watch this webinar to learn how you can implement this technology and make remarkable sound of electrified vehicles inside out.