Industry Insights

Simcenter Active Sound Design for automotive Solution brief

Siemens Digital Industries Software

The Simcenter™ Testlab™ software At the same time, legislators have Challenges portfolio for sound quality engineering imposed legal requirements for AVAS to • Develop compliant AVAS sound that is includes a solution for active sound be installed in quiet vehicles to warn also a recognizable brand sound design for automotive. It’s an advanced pedestrians when driven at lower speeds. sound quality engineering tool for • Enhance interior noise to match New active sound design teams are design, validation, tuning and deploy- required sound quality perception taking up the challenge to design, vali- ment of interior sound enhancement for date and implement these sounds. They hybrid/electrical vehicles (HEVs) and Solutions emerge as cross-functional teams, shar- internal combustion engine (ICE) vehi- ing expertise from different domains. On • Use Simcenter Testlab Sound Designer cles, and for mandatory exterior acoustic one hand there are the noise, vibration vehicle alert system (AVAS) sounds. It’s • Validate inside the vehicle with the and harshness (NVH) experts that engi- based on state-of-the-art sound synthesis Vehicle Unit neer interior and exterior sound quality techniques. It’s complemented with by working on acoustic transfer paths, • Use AVAS unit to synthesize sound hardware to evaluate and tune sound using isolation material for masking noise signatures in real-time in the target (or • Interface to vehicle’s CAN bus with and shaping engine orders with struc- mule) vehicle, or on a vehicle simulator. CAN Gateway tural modifications. Creating an immersive driving On the other hand, there are the sound Results experience designers that have mastered expertise • Design, validate or tune sound With engine downsizing, weight reduc- from the audio domain. They design and signatures in studio or target vehicle tion, cylinder deactivation and compose sounds that match a certain • Design sound ready for production on electrification of the powertrain, the brand image of a product. Tier-1 audio supplier hardware sound characteristic inside the vehicle The Simcenter Active Sound Design has changed. An often-heard remark • Mask acoustic issues late in the solution combines these two expert about HEVs is they have great accelera- development cycle domains into a single software and tion, but they lack the sound perception hardware solution. Design, validate, tune and emotion that drivers expect to hear. and deploy both exterior and interior sound to comply with legislation and match the expected sound perception.

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A single environment to design, validate, tune and deploy active sound Simcenter Testlab Sound Designer is used to create sound signature models that are parametrized in function of vehicle parameters, allowing you to design complex sound scenarios that fit an auto original equipment manufacturer (OEM) Simcenter Testlab Sound Designer - from design to deployment for production in one tool. brand and still deliver differences between vehicle models. Simcenter Testlab Sound Designer can change include grain position and These sound signatures can then be enables the creation of unique signatures duration, pitch change of the grain and a validated directly inside the vehicle. This for hybrid/electric vehicles in several certain randomness to make sure one can be the target vehicle, or, as it is often sound layers that use one of the follow- never has the perception of listening to a not available, a mule vehicle. ing two methods: granular synthesis and/ looped sample. or engine order synthesis. All parameters used to synthesize the Engine order synthesis has been around sound can be changed in real-time, • Granular synthesis creates a rich and for quite some time. It synthesizes sine allowing the user to tune the sound in a lively sound based on a designed or waves with different phases in function real dynamic driving environment. recorded sound sample. It is then of vehicle RPM or speed. This can be The final sound signatures can then be parametrized in function of vehicle done based on recorded engine orders or deployed on the audio amplifier hard- speed or torque shaped orders and for different engine loads. Best results are obtained if a ware of any Tier-1 supplier. Several major • Order synthesis allows you to design certain ”dirtiness” or ”randomness” is audio chips from Analog Devices (ADI), sound signatures emulating or added. Engines never run at exact RPMs Texas Instruments (TI) and ARM are enhancing combustion engines. This and modeling different variances into the already supported, while the solution can can be accomplished by starting from synthesis greatly increases the liveliness be extended for custom audio hardware scratch or using an existing engine and naturalness of the sound. Even platforms. This makes Simcenter Testlab sound and synthesizing the delta adding effects of additional components, Sound Designer a vendor-neutral solu- between the existing noise and the such as backfires, further increases the tion, as it does not depend on the desired target fast-changing reality of which Tier-1 realism and directly addresses the audio supplier gets to deliver the Granular synthesis comes from the music emotions of drivers. The result will sound hardware. industry and as such is well known to just like a combustion engine, but it can sound designers. It does not aim to take a long time to get it right. replicate the mechanical properties that Designing sound signatures Finally, after combining two of these make combustion sound so characteris- Sound signatures can be easily designed synthesis layers, several advanced meth- tic. The chosen sound sample, typically and fine-tuned using graphical controls. ods can be added such as a Shepard layer no longer than 2 seconds, can come from They are parametrized in function of for low frequency content. They enable anywhere. It can be the natural sound of dynamic vehicle parameters: speed, synthesized sounds to be perceived as a rolling ocean wave or a wild animal. It engine torque, throttle, revolutions per natural and rich. minute (RPM), gear. Synthesizing is then can be a recording of a musical instru- done in real-time either in the studio or ment, combustion engine or a purely During the design, Simcenter Testlab the sound lab while driving in the vehicle composed synthetic sound. As long as Sound Designer can be used to mix or on a vehicle simulator. Parametrization the sample reflects the brand sound and sound signatures on top of a recorded is done by user input, predefined driving positive perception of future vehicle driving sound, using drive cycle data. profile or with a CAN interface with the buyers, granular synthesis is able to This is done using a dedicated drive vehicle or simulator. elevate it to an entirely new vehicle simulator module, which replays sound. Parameters that sound designers predefined or recorded drive profiles. Vehicle unit allows longer term evaluations. AVAS unit. Real-time tuning.

Validation and tuning runs without a PC but interfaces with the Frontloading AVAS compliance Whatever sounds great in the studio or Simcenter Testlab Sound Designer appli- AVAS sound signatures in Simcenter on a simulator must be validated in the cation for uploading sound signatures Testlab Sound Designer are typically vehicle. This is done in different phases. and real-time modifications of the sound based on granular synthesis. AVAS design synthesis parameters. includes vehicle integration steps to First, the personal computer (PC) can be account for the influence of the sound of interfaced with the vehicle using a Deploying for production the system and housing of the AVAS Simcenter Testlab Sound Designer CAN It’s important to start with the end in speaker, as well as the impact of the Gateway. This connects the vehicle’s CAN mind: The final validated and tuned mounting location. This ensures that bus to the PC. The sound synthesis is still sound signature needs to run in a after integration in the final prototype, done on the PC and the audio output can production vehicle. Several options are the AVAS sound is evaluated for mini- be connected to the vehicle’s head unit, possible, and all are supported with mum noise testing in the same way as it or an additional speaker system. The Simcenter Testlab Sound Designer. In all was designed. parameters determining the sound cases, the synthesis engine needs to be synthesis remain editable in real-time on A dedicated AVAS check software module interfaced with the audio DSP chip of the the PC application, just as during the is used to evaluate the sound against selected Tier-1 supplier of the head unit initial design of the sound in the studio. legal requirements. It supports the major or audio amplifier. Several versions of standards in Europe (United Nations Next, for final tuning and longer-term ADI Sharc, NXP ARM and TI are supported Economic Commission for Europe, UN evaluations, a dedicated Simcenter and extendable to others. More complex ECE Regulation 138), United States Testlab Sound Designer Vehicle Unit is sound signatures require chips with (Federal Motor Vehicle Safety Standards, used. The sound signatures for in-vehicle enough memory and processing capac- FMVSS 141) and its derivatives in China enhancement then runs on the audio ity. This solution runs in parallel with and Japan. Together they support sound digital signal processor (DSP) of this other applications such as audio multi- designs that are not only pleasant and vehicle unit . It’s typically connected media, navigation, phone integration or brand-aware, but also comply with directly to the vehicle’s CAN bus. Its audio active noise cancelation. legislation from the start. This is accom- output is directly connected to the vehi- plished by measuring the transfer cle’s speaker system. The vehicle unit function between the AVAS speaker location and the pass-by noise (PBN) microphone and loading that into the Simcenter Testlab Sound Designer software. A matrix with green and red cells indicates if each required check and standard passes the applicable criterion. This is an efficient way to front-load compliance.

AVAS check front-loads compliance with standards. Simcenter Testlab Sound Designer Comprehensive active sound design works in conjunction with a dedicated Simcenter Testlab Sound Designer allows Simcenter Testlab Sound Designer AVAS the creation of unique sound signatures unit, developed in cooperation with a for hybrid and electric vehicles. The Tier-1 audio supplier. This unit includes solution runs the full active sound design the speaker and audio DSP to generate process from first design to delivery for the AVAS sound and interfaces with the implementation in production vehicles, vehicle using CAN. For real-time tuning capable of running on any audio and vehicle integration of the AVAS amplifier. sound signatures, the Simcenter Testlab These active sounds create the immersive Sound Designer CAN Gateway is used. experience for the next generation of The integration work typically includes vehicles on the streets. tuning the effect of the speaker on the exterior sound perception. In a later phase, for longer term evaluations, the AVAS unit can be connected directly to the vehicle’s CAN bus. Dedicated CAN message identifications can be selected to communicate with the device. Implementation for production vehicles is done in the same way as for interior sound: The AVAS signature has to be transferred to the selected audio amplifier or self-contained AVAS unit.

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