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Exclusive: Harman, Ansible Motion reveal the importance of sound in DIL simulation

'Driver-in-the-loop' automotive simulation is an unusual application for AKG headsets

Although cars have become increasingly quiet in recent years, ground-vehicle simulation company Ansible Motion emphasises the importance of sound for accurate driver feedback and has been working with Harman to ensure realistic reactions and more accurate vehicle development. PSNEurope talks with Ansible Motion’s Kia Cammaerts and Harman’s Matt Fisch to find out more

Today, simulation is widely used as a tool within the automotive industry for developing new road-car technology. It’s both a cost-effective and environmentally friendly method of trialling new products before prototyping. Yet the effectiveness of a driver-in-the-loop (DIL) simulator is dependent on its ability to create an accurate response within the driver, who has to believe that he or she is driving a real car and react accordingly in order to give insightful feedback during development.

It’s physically impossible to create a DIL simulator that replicates a vehicle’s movements exactly with all the correct g-forces, so simulator developers must go above and beyond when creating the environment. Despite cars getting increasingly quieter, the accuracy and realism of the simulator’s audio aspects plays a significant, and often overlooked, role in eliciting this emotional response.

British ground-vehicle simulation company Ansible Motion, founded by Kia Cammaerts (pictured), is increasingly relying on technology from Harman to deliver the high-quality, accurate audio feedback needed for this response. “At Harman we have an in-depth understanding of sound, the importance of sound quality and how it can create emotional reactions, whether that sound is a piece of stirring music you listen to on the move, rousing sound effects from a movie you watch at home or an exhilarating engine roaring in your car,” says Matt Fisch, vice-president of global engineering, global automotive audio, in Harman’s Lifestyle division. “All these sounds have the ability to elicit an emotional response.”

A 2009 report from Sweden’s Lund University put forward six mechanisms through which emotions may be produced when the brain reacts to sound. These include ‘emotional contagion’, which is where we perceive the emotion expressed by a piece of music, and ‘music expectancy’, which is tied to our experience with music (such as an unfamiliar variation on standard note progression causing feelings of surprise and curiosity).

These mechanisms also include ‘brain stem reflect’ – an inborn reaction activated when the characteristics of the sound signal an important or urgent event, such as the sound of a car horn or driving over road rumble strips – and ‘evaluative conditioning’, when an emotion is elicited from a sound heard repeatedly in a certain environment, leading to an association between sound and setting.

These last two mechanisms in particular come into effect within a simulator environment. “Loud sounds, such as driving over rumble strips, a car horn or an engine revving at maximum, activate the instinctive fight-or-flight reaction in the brain and can be crucial to ensuring human survival, even in the modern world,” explains Cammaerts. On hearing a car horn the human brain and body quickly respond to ensure movement out of harm’s way, which is then followed by tranquilising chemicals that counteract the stimulating chemical.

These are extreme examples of emotive sound, but there are a vast range of audio cues that elicit a response when driving: speed, through wind, tyre and engine noise, acceleration via the engine revving, the environment, road disturbance, traffic, obstacle noises. It isdelivery of these sounds for the full and rounded sensory experience that is ‘mission-critical’ for Ansible Motion in DIL simulation.

“We get to see the effect of this emotional reaction regularly in our simulator,” continues Cammaerts. “If the driver crashes, you can see – and often hear – that they were fully immersed in the driving experience by the way that they react to hitting track Armco [crash barriers] or other objects on the simulator course.”

This accurate sound is delivered to the driver through specially selected products from Harman’s family of brands. An AKG HSC271 headset ensures that sound of the highest quality is delivered to the driver inside the cockpit, featuring an audio frequency bandwidth of 16–28,000Hz and sensitivity of 104dB SPL/V. “Good-quality audio delivery is essential for us,” says Cammaerts. “We chose to use Harman as its product portfolio delivers the vast range of frequencies to the ear effectively.” The sounds, and their delivery through the headphones, also masks the noise of the simulator itself, adding to experience.

“The AKG HSC271 is typically used by broadcast engineers, and is an extremely high-performance product,” says Fisch. “It provides excellent comfort, optimum ambient noise reduction and outstanding audio quality, so was the perfect solution for Ansible Motion’s requirement within the simulator. We want to help the driver forget that they are wearing headphones and to focus on the task in hand and this reliable headset achieves this.”

The headset (pictured) is also equipped with a high-performance condenser microphone, which allows the driver to deliver feedback to the engineers in the simulator control room and the crew to speak to the driver. “Although-quality audio input into the cabin is essential, it’s also really important for the engineers to receive accurate and clear feedback from an operational perspective,” comments Fisch. “This two-way communication is essential for safety and system operation, and this high-performance condenser mic ensures a clear output.”

This is continued with four in-wall JBL speakers that provide playback from the simulator into the gallery, allowing the engineers to understand exactly what is being seen and heard by the driver while observing their reactions. A matrix mixer and four-channel Lab.gruppen amplifier deliver concert-quality, low-latency sound while adapting to a wide variety of demanding load conditions.

In addition to supporting emotional immersion in the simulator, the audio received by the driver also contributes towards eliminating simulator adaptation syndrome (SAS). “Simulator sickness is really prevalent, which is why it’s earned itself this special name,” explains Cammaerts. “The human body is adept at controlling vehicles designed to suit our abilities, but if we receive feedback that does not fit with what we expect then we become disorientated and confused. It’s a key element behind some drivers experiencing motion sickness in DIL simulators, but the accuracy of the sound feedback, which complements the visual and motion cues, helps to eliminate this.”

The union of Ansible Motion’s DIL simulators and Harman’s car-audio technology illustrates that sound will continue to play an important part in the future of the car, its development and the final product for years to come.