The science of sound

In a busy world where so many different mediums compete for our attention, it comes as little surprise that so many people consider their car a refuge where they can enjoy time to themselves – cocooned from the outside world.

A recent study conducted by the International Federation of the Phonographic Industry found that more than 70 percent of respondents nominated their car as their preferred place for listening to music – a fact that Audi has always taken very seriously in the design and execution of its celebrated interiors.

“That’s why our goal is for music to sound better in a car from Audi than it does at home,” says Dr Tobias Gründl, head of Audi’s Sound and Acoustics Development department. 

But given the great disparity in physical size between different Audi models, and the fact that the interior of a car is a particularly difficult acoustic space means ensuring optimal sound reproduction for each model’s interior creates its own special set of challenges. The interior of a car is a particularly difficult acoustic space, full of reflecting and absorbing surfaces. In addition to the reflection issues, Audi’s sound engineers have to factor in the different distances between speakers and listeners’ ears to ensure that everyone in the car receives the full benefit and richness of the sound.

“The challenge for us has been to create this sound pattern in every vehicle segment with their different kinds of spaciousness. Whether they get into an A1 or an A8, it always sounds uniquely like Audi. That continuity of quality requires a lot of expertise in the impact and balance of frequencies,” says Gründl.

“In the compact A1, we’ve been able to integrate intelligent sound architecture that can absolutely keep up with the higher segments – quite simply by using the windscreen as a reflective surface for 3D sound.”

Speakers too can be controlled with individual time offset so that the sound reaches each listener at the same time regardless of where they in the vehicle.

Audi is a leader in creating a unique, three-dimensional stereophonic experiences and has been using the soundCUBE software developed in house which allows audio developers to control 100 percent of the technology that they use in an Audi. Thanks to SoundCUBE, the experts can choose the best algorithms available on the market and integrate them themselves.

The use of this software allows a tremendous number of new possibilities for sound presentation utilising the existing hardware that is already a known commodity. To that end, Audi has always worked with leading audio specialists, the Bang & Olufsen 3D sound systems for example, having long been a staple in many models, offering state-of-the-art immersive sound that needs to be experienced to be fully appreciated.

With the new Audi Q4 e-tron models, Audi is working with Sonos for the first time, the brand’s ‘authentic, energetic sound’ fitting perfectly with Audi’s sound philosophy in its compact models according to Gründl.

“The new Q4 e-tron is Audi’s entry point into the premium world of electric vehicles. It is increasingly aimed at younger generations and young families and those customers know Sonos from home. Now, for the first time, we’re bringing Sonos where people like listening to music most.”

The Sonos system also allows different listening options that will appeal to customers interested in the Q4 models.

“For the first time, people can use familiar sound settings to make tonal changes in the timbre that will create more emotionality in the interior,” says Gründl. 

“The back seat can have more bass and be filled with louder sound while the driver and front seat passenger can listen at half the volume and a more neutral balance so they can concentrate more on traffic – or spare their nerves.”

Of course the very best hardware components and software can only do so much depending on the sound source.

“Playing music from a smartphone via Bluetooth is very convenient, of course. But as a sound engineer, it makes my heart bleed a little, because Bluetooth reduces the sound quality significantly.

“That's because of the limited bandwidth … as a transfer technology, Wi-Fi offers a better solution for this, given that the bandwidth for the transfer is significantly larger. Personally, I would prefer to use an SD memory card for WAV with 24 bit and 48 kilohertz. Soon it will be possible to use the 5G mobile communications standard to stream high-resolution source material. Then the car will finally become a streaming centre for sound and image.”

Then there are the possibilities offered with e-mobility, which Dr Gründl says offers the chance to make sound come alive even more intensively.

“We can’t forget that people who get themselves an e-car for the first time will miss one familiar sound – the engine. E-mobility is presenting us with new acoustic challenges and making new sound strategies necessary. For that, we’re keeping the holistic approach of immersive stereophonic sound in mind. Autonomous driving and communication with the vehicle in the form of voice-operation are also important factors in the conception of Audi’s future sound and acoustic architecture.” 

In the end, that holistic sound experience is an objective and a benchmark – from hifi to switch clicks, from phone conversations to warning signals, from podcasts to symphony concerts.