Automakers and Audio Companies Are Pushing In-Car Music Technology Farther Than Ever

Using the most voodoo of automotive sciences, premium sound systems lean on both expert ears and virtual modeling. The result: Listening bliss.

Mercedes-Benz

Elliott Scheiner knows what music should sound like. The Grammy Award-winning producer and sound engineer has spent a lifetime developing it for the world’s best musicians: Aerosmith, Paul Simon, Eric Clapton, the Foo Fighters, Beck, Steely Dan, the Eagles, Queen, and many more. He can tell when something isn’t right, and knows how to fix it.

Take Van Morrison’s “Moondance.” You know the song. You can probably summon the music perfectly in your head just by reading the lyrics, so vivid is Irish legend’s 1970 composition. Scheiner was the original mixing engineer on that track, but during the recording sessions, something felt off. 

“I couldn’t figure out what it was so I went in and put my ear right by his guitar as he played,” Scheiner recalls. “It made sense the way he was playing it, but when I got back to the control room it just wasn’t there. So I changed the placement of the mic and added some equalizer, and it sounded much better. To hear Van’s guitar in a recording and know it’s accurate, you really have to know what the sound should be.”

In more recent years, Scheiner has taken that golden ear of his and turned it toward car audio systems, helping upscale automaker Acura fine tune the sound system it launched first in the TL model in 2004 but which it now offers across its lineup. The most recent top-end variant, dubbed ELS Studio 3D and produced in partnership with Panasonic, is a 710-watt option in the newly redesigned RDX. It includes 16 speakers, with four in the headliner for a more enveloping sound. The idea is not merely to create a surround-sound effect, but to precisely coordinate the arrival of different elements of the music to your ears, something Scheiner helps validate in testing. 

“Time delay is important,” explains Mark Ziemba, Panasonic Automotive’s audio systems manager. “We want to precisely align the speakers—tweeters up front, midrange door speakers, and the overheads—so the music arrives at your ear at the right time, and one speaker isn’t getting there before the others. Elliot mixed all these records and knows the artist’s intention, so he’s able to convey that all to us so we can better gauge if it’s right.”

Above: The ELS Studio 3D stereo in the 2019 Acura RDX

Scheiner says creating that system, which he describes as generating music that feels simply “in the air,” as though originating from speakers in a good studio, meant tapping his vast memory for experiences similar to that he had with Morrison. “Most car companies are guessing at what they think might be the real sound,” he says. “We fashioned everything based on my experiences, what I remember the sound to be like. For instance, I spent six months just mixing every song and every guitar part on Steely Dan’s final two albums, Aja and Gaucho. So when we get in the car to test it, those are two of the records we use.”

Placing speakers up in the headliner is a new twist that at least one other manufacturer—Mercedes, in its current S-Class flagship sedan—has embraced. But it’s one of countless strategies automakers have pursued, usually in collaboration with high-end audiophile brands and independent experts, either to create acoustic experiences that can match or often exceed the systems music fans experience at home or simply to meet the overall standards of a high-end brand, regardless of whether the owner knows his Van Morrison from his Van Halen. As a result, luxury rides now come with dozens of speakers in total and system power in the 1,000-watt range. They’re world-class rolling boom boxes now.

The market for such premium automotive audio systems is huge—and growing. According to research published last year by automotive industry analyst IHS Markit, car buyers in the U.S. were willing to pay an average of $573 for a premium audio upgrade in their new cars, and branded audio systems were expected to grow from 11 million units sold in 2016 to 14 million by 2023. The survey also found that 81 percent of buyers indicated that a brand name audio system would influence their vehicle purchase decision. Sony, Bose, and Pioneer ranked as among the most influential brands globally, but the world of ultra-premium carmakers includes a variety of boutique audiophile brands unlikely to register in global surveys. Bentley, for instance, works with Naim for its audio systems, Porsche and Mercedes with Burmester, and Jaguar with Meridian. Some car brands work with multiple providers across their lineup; some tap one of the audio sub-brands owned by still bigger names. Harman, for instance, owns Bang & Olufsen, Bowers & Wilkins, JBL, Lexicon, Infinity, Mark Levinson, and Revel, among others.

Any certified music fanatic can explain this surging obsession easily: Great music delivered through a magnificent system can convert a mundane commute or epic road trip into rolling theater-of-the-mind, where music, machine, brain, and an enthralling stretch of road fuse into a blissed-out singularity. Whether your jam is the classic rock or classical, pop or alternative, country or rap, a great car audio system can make your stress melt away—or help you find your flow while stitching together fast mountain twisties. Most premium carmakers know these feelings well, and are only too happy to accommodate them. 

“Audio is a key part of our customers’ overall experience,” says Bentley Motors audio engineer Mike Hanks. “Music is such an emotive medium, and it has a huge impact on people. For us, it’s critical.”

Mercedes-Benz

A Burmester speaker in a Mercedes-Maybach

Drivers and passengers are captive audiences

The challenges of achieving great audio in a car however, are tremendous. Though engineers working on home or studio systems have space to play with generous size and weight constraints, vehicles are compact environments, filled with disparate materials that add or subtract from the sound. Acoustics are hampered by road and wind noise, vibrations, and the sound of the engine. Add in such contemporary variables as automatic stop/start systems that shut off the engine at stoplights and electric or hybrid vehicles that further monkey with background noise levels in often-unpredictable ways, and you start to see the problems engineers face.       

On the other hand, cars have the advantage of providing a captive audience. “In general, small spaces are not good listening rooms, but with cars you at least know the venue,” says sound engineer Alfred Svobodnik, president and CEO of the MVOID-Group, a sound design firm near Stuttgart, Germany, that consults with premium automakers on their high-end systems. “With home hi-fi systems, you have no idea where the customers will sit or place the speakers, or even the size of the room. But in a car you can really customize the sound system so that it’s good in all seating positions.”

There are still effects like acoustic resonance and huge sound-pressure variations inside the vehicle, as well as significant packaging problems, with almost no space left over inside a car for woofer, subwoofer, and tweeter placement precisely where you want it. In light of this, says Brad Hamme, senior manager of acoustic engineering for Harman, manufacturers are also pushing audio engineers to reduce the size and mass of speakers—though not, of course, at the expense of sound quality. 

“Ultimately, premium high-dollar systems need to be really top-line in sound quality,” he says. “The carmakers recognize that and tend to give us a bit of leeway.”

Bentley

Bentley Continental GT interior

Automakers and audio companies: Making beautiful music together

Carmakers also hope genius solutions will raise the bar without complicating the car’s core engineering. From purely a hardware perspective, audio specialists are working to optimize amplifier and speaker integration with this in mind. Hamme notes that everything from more compact wire harnessing to high-efficiency speakers that require less power to low-mass neodymium magnets are able to deliver premium sound while taking up minimal space in the vehicle. 

“Efficiency and performance can be balanced together,” Hamme says. “There are a lot of technological advances now seeing the light because of the current condition of the automotive market.”

Speaking purely musically, all the engineers interviewed agreed that one of the key customer cravings is for improved bass performance, prompting manufactures to come up with better strategies for subwoofer placement, such as in the floor area near the driver. To Scheiner, such strategies go a long way. “Lo-fi audio doesn’t sound natural, such as in cars with one-note bass,” he said. “So you get this sudden, really loud bass not that then disappears, and that generates listening fatigue. You want a nice, powerful, and accurate bass that does what the original recording would do.”

Software enhancements further build the you-are-there quality. Harman, for instance, has begun taking live measurements of different world-class venues in order to create digital signal processor (DSP) algorithms that create virtual venues, letting passengers feel like they've been transported to, say, Sydney Opera House. Unveiled at CES a few years ago, the venue-specific DSPs will be launching in products soon, Hamme says—adding that he was skeptical of the effect himself until he tried it. (“I thought it would be chintzy, but I genuinely enjoyed it,” he says.) The system also uses microphones to gauge interior activity and dial in things like clapping sounds in the recording, so it feels like you’re actually in the room.

Others work to tune the systems to accommodate specific music styles, via more-familiar algorithms. But even these evolve with the times and the technology, and involve intricate tuning. Bentley’s "classical mode" takes out some of the harshness of the music and turns up the active bass, Hanks says, since so much of the low end of classical music can get lost due to engine and road noise that enters the cabin at similar frequencies. There’s also a spoken-word mode, such as for podcasts, that focuses on speech, and a digital media enhancement that compensates for any losses from Bluetooth connectivity. (Pro tip: Cable connections are always better than Bluetooth when it comes to audio quality.) Finally, there’s the “enhanced” mode, a.k.a., the dealer demonstration mode. It loads up the bass and treble for a more springy performance. 

“Dealers love that mode because it sounds phenomenal, but you wouldn’t want to drive five hours like that,” Hanks says. “It’s so tiring.” In all cases, the computer “steers” music based on the type and the ambient conditions to the occupants with precision down to five millimeters of accuracy using the DSP alone, and the precision bass transducer produces the bass feel without disrupting conversation inside the car.

Being a performance-car maker, as well—witness the 200-plus-mph Continental GT—Bentley also engineers its sounds to match specific qualities of the vehicles they’re built into. The company spends hours listening to each system at different speeds, given that the acoustic environment at 50 mph is much different than it is at 180 mph. So Hanks’s team builds has the equalizer adjust with every kph increase in speed. The convertible version of the GT, which has 20 speakers in total, gets its own additional tweaks, since bass tends to be lost even more with the roof down. As a result, there are eight different modes it can enter during open-air driving that bump up the bass two or three decibels, though all of this is done automatically. The driver, Hanks said, should only hear great music. 

His proof that the hard work is paying off: consumer feedback. “We’ve had customers tell us they will stay in the car until the track is done playing even if they’ve arrived at their destination,” he said. “We love to hear that.”

Mvoid

An audio-focused simulation of a car's cabin

Science-ing up the sound

Achieving all the right solutions for a specific vehicle—and every model invariably gets a custom tuning—means a lot of experimentation and a lot of listening. Most car companies have someone like Elliot Scheiner on hand, whose role is to gauge the payoff of a given strategy. Hanks’s team at Bentley is a small but committed group of audiophiles—three audio engineers, and one so-called “golden ears guy” whose sole job is tuning the systems. 

“He goes out, listens, and when he comes back he provides the small or large tweaks to smooth out a certain harshness, or mask something, or suggest a frequency change to filter out something else,” Hanks says. “We take measurements, repeat trials, and rely on our ears. It’s very much a hands-on approach.”

But objective measurement is increasingly valued by carmakers seeking to supplement the instincts of all those well-trained ears. Hamme says Harman is working to learn what actually constitutes “great” sound. “We have a very large benchmarking team that objectively measures subjective opinions of listeners—so what’s good sound and what isn’t,” he says. “There can be a lot of snake oil in premium audio, so we are studying how to deliver an experience based on what people really want.”

As the consumer base has grown more educated, Hamme says they’re better able to pick out what they want in this fashion, and he says that those subjective opinions are remarkable consistent. During double-blind testing, the music qualities and preferences people across a wide range of countries register today shake out in the exact same order that they did 15 years ago, Hamme explains—suggesting ideal audio is very much a definable thing across different cultures.

Still, analyzing and quantifying actual audio performance via hard data remains an elusive goal, though progress is being made. Svobodnik’s company, Mvoid, helps do this by providing manufacturers with virtual tools for modeling an audio systems performance during the design phase. “Sound is quite a complicated thing, especially sound quality, and it’s pretty tricky to measure,” Svobodnik says. “The carmakers want their own sound affixed to the car, so we help them with that process.”

Mvoid's simulation software, now in use by clients such as Mercedes, Bentley, BMW, Audi, Jaguar, Volvo, and Harman, takes vehicle data such as the acoustic performance of different materials and analyzes individual speaker performance inside the cabin, factoring in sound pressure distribution and reflections that vary from surface to surface. It also helps determine vibration levels from the sound hardware itself. For instance, though making speakers more lightweight has overall benefits to the design of the car, lighter speakers can introduce their own vibrations that add rattles to the soundtrack and a general feeling of stress. 

“One board member at a luxury German carmaker said the vehicle should be like a wellness spa for passengers, with no stress,” Svobodnik says. “But if you can hear stress in the speaker, you’re not there. If the speaker is overpowered it doesn’t sound relaxed, spectrally or spatially.”

Ultimately, the goal is to determine the optimal placement for each speaker based on this data and the performance of the other speakers in the system. This, Svobodnik says, generates a unified whole, as if the system were acting as a single speaker. His software can also help define how and where speakers should be aimed and timed to ensure the sound arrives at different seats at the right time. Getting all this right early in a vehicle’s design process is important, given that once other structural and design elements are locked in, making changes can be complicated and expensive, if not impossible.

Much of this works in the service of “staging” the music—generating the feeling that the sound is originating in front of you, as though you were at a performance. Virtual simulations are used to determine the way a system; engineers listening to demonstrations through Mvoid’s software can determine if the quality of a live performance is present, or if subtle distortions strip that feeling away. Svobodnik’s goal is to minimize the subjective interpretation of this as much as possible. “We try not to rely solely on personal listening tests of the manager, which can easily be affected by how he or she slept the night before, problems with the kids, etc., but rather on a more scientific approach,” he says.

Bentley’s Hanks says the approach has paid off. “We get into digital prototyping with Mvoid early in the design process,” he says. “Before we build the car, we start playing around with speaker locations and mountings, and even the stiffness of the thing it’s mounted do. Then we run the prototype and validate it with an existing car. When we compare the two, we find the simulation to be 70 to 75 percent accurate. We’ve won some battles over speaker placement through these virtual demonstrations.”

Mvoid

Mvoid's software in use

Listening in the future

All this innovation points to a dynamic possible future for in-car audio. Svobodnik says, first of all, that smaller entry-level cars will become significantly better as science and engineering improve acoustic performance, hopefully ending the era of cars with nothing more than four tinny speakers on the doors. The natural demand for better sound will improve this, even though carmakers are placing tighter and tighter constraints on the hardware being installed in vehicles. 

Hanks says they’re paying more attention to the weight and power consumption of individual components, particularly with regard to vehicular electrification. From his own perspective, he also wants to see more intelligent systems that can automatically access the best DSP algorithm for the music being played—even tapping libraries from competing DSP manufacturers—and automatically customizing performance, such as detecting when the driver is the sole occupant and setting the system up for driver-optimized audio without him or her needing to request that themselves. 

“There are hundreds of other things we’re looking at—use cases that make it better for the customer without them having to go in and change menus,” he says. “It should just work.”

Looking even farther into the future, Harman’s Hamme adds that autonomous cars will further challenge the audio industry, given that they’ll become rolling home theaters with changeable interior seating positions, including more rear-facing chairs. Systems that can automatically keep up with shift-on-the-fly user demands via adaptive sound systems will be critical. 

For cars that are still being manually driven, the precise tune-ability of future systems will create more subtle and nuanced interactions with the car. Navigations systems, he suggests, won’t just provide verbal prompts—i.e., “turn left”—but will acoustically guide you there, as well. The sound will progressively shift its source to emanate from the direction in which you’re supposed to turn, making a more fluid and instinctively grasped instruction. Of course, it'll also cough up a pretty kick-ass performance of “Moondance,” as well.