As automotive design races towards a brave new future, digital signal processing is making our cars increasingly enjoyable places to be
13 October 2014

As you’re probably aware, cars are getting smarter.

Even affordable cars have increasingly clever hybrid powertrains, adaptive cruise control and the ability to recognise traffic signs. In the next few years, give or take, they’ll also be able to talk to each other and drive themselves. Amid all the noise around experimentation with autonomous vehicles, smart cities and machine-to-machine communication, there’s an area that receives less attention. And it’s arguably the most important of all – because it’s where you and your passengers sit.

In-car upgrades

The cabin is going through a ‘smart’ revolution of its own. From the way we access our smartphones’ functionality and interact with instruments (see BMW’s AR dash) to the seating we luxuriate in, all aspects of the in-car experience are being scrutinised and improved.

Audio is no different. Since the late ’90s, the computers that have given cars the ability to improve our drives have also been applied to improve our audio, through a process known as DSP – digital signal processing. DSP is the modification and optimisation of a signal: applying computing horsepower that changes a stream of data to improve efficiency or performance. In-car computer processing can be used almost anywhere data is gathered, interpreted and acted upon: active suspension, torque vectoring, voice recognition and a huge amount more besides. With car audio, DSP is applied to optimise the sound we hear.

The DSP difference

Gone are the days when mounting a pair of giant subwoofers in the boot constituted a cutting-edge in-car audio experience. The modern car’s cabin has speakers integrated throughout: in the doors, in the pillars, even under the seats. But that presents a challenge.

Traditional stereo hi-fi has us sit in front and between two speakers, so we’re used to feeling as if we’re positioned in the sweet spot, centre stage, with each instrument placed precisely in what hi-fi enthusiasts refer to as the “soundstage”. But with multiple speakers positioned in unusual places in a car, and the various angles and materials that constitute an interior (seats absorb sound waves while metal and glass reflect them, for instance), it’s much more complicated.

“All the drivers are actually mixed together and you’re sitting in a kind of chaos”, says Morten Hermansen of Danish audio specialist Dynaudio, the company responsible for Volkswagen’s premium audio systems. “You really have to have control of every driver’s timing, and frequency response, and the way they work together.” That’s why DSP is used to customise the sound of each speaker independently. Dynaudio painstakingly maps how each speaker behaves and how every curve and surface of the interior reflects sound. Then, by tweaking delays, balance and frequency response, the signal fed to each speaker is manipulated so that its sound hits you (or anyone else in the car) at precisely the correct time. This puts you in the sweet spot, as if you’re listening to a home hi-fi or, even better, sat right in front of your favourite band or orchestra. DSP’s trick is to create order from the chaos.

So effective is this technology, it’s now being applied outside of the car, too. Dynaudio has taken all it knows about DSP and used it to ensure that the speakers in its new family of intelligent home audio systems, Music, perform at their best no matter where or how they’re used.

Each Music system’s DSP-derived RoomAdapt feature senses where it’s been placed in the room and continually adjusts its sound to deliver music that sounds just-so. Whether up on a high shelf or bang in the middle of a table, Dynaudio claims it will perform at its best. Meanwhile, its NoiseAdapt feature automatically adjusts tone and volume to compensate when the ambient noise in the room gets louder or quieter.

And, perhaps smartest of all, its Music Now algorithm learns your music tastes and creates bespoke playlists full of music you’ll like, accessed at the touch of a button. You’ve heard of the self-driving car; meet the self-driving hi-fi system.

It’s not just about computers

But DSP technology is just one component of a great modern home hi-fi or in-car audio system. Dynaudio’s engineers spend countless hours listening to its speakers and car installations, even tweaking the three-door and five-door versions of the same Golf independently, tuning by ear to ensure they are performing at their best.

Proven audio engineering is crucial, too. That’s why Dynaudio uses the same technology (and ears) to create its home hi-fi speakers, its pro studio monitors, the new Music systems and in its in-car installations as it does to produce its range-topping Evidence Platinum hi-fi speakers.

Music that drives you

If great in-car sound is important today, consider how vital it will be in the future, when we’re spending more time in our cars but driving them less. Engaging autopilot for the commute to work is a waste if you’re bored; imagine filling that time with a film accompanied by a powerful, pristine surround soundtrack.

This kind of start to a working day really isn’t far away – almost every big brand plans to have highly autonomous models on sale by 2021. Dynaudio’s DSP-augmented installations are ready to deliver that kind of audio experience on the road today. And with Dynaudio Music, now you can bring it home, too.

For more information on Music, Dynaudio’s range of intelligent music featuring DSP technology, click here.

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