CES 2015: Making sound squabbles a thing of the past By Leo Kelion

Technology desk editor. Las Vegas Published duration 10 January 2015

image copyright Thinkstock image caption They might be happy now but that could change as the rows break out over what they listen to

It's a common problem for anyone embarking on a road-trip with family or friends.

Battles are waged over who chooses the sound track for the trip. It can lead to arguments, stress and ultimately resentment that can linger throughout the journey and beyond.

Now, one company thinks it has found an answer - a way to create different audio zones in a single vehicle, with little spillover of sound between separate spaces.

But is Harman's solution so elaborate that it will be priced out of the range of most motorists?

Sonic clutter

The US company invited the BBC to be one of the first to try out its new technology, which is being shown off at an invite-only fringe venue at CES.

There, in a darkened room, sits a customised Lexus four-seater.

The vehicle's existing sound system has been enhanced by micro-speakers placed in the headrests of each seat and a set of thin loudspeakers inside the roof.

By combining this tech with specially-designed software, the firm is able to let each passenger hear a separate source of audio while radically reducing the amount of what it calls "sonic clutter" created by the other sources.

"We are able to play the desired source of audio in a particular seat but also simultaneously play the opposite of the other sources of audio from the other seats, thereby cancelling their sounds out," explains the project's lead engineer Christopher Ludwig.

"We can do that for any sources of audio in any particular seat, thereby creating personalised audio zones.

"[The other sounds] don't completely go away but we're achieving about a 15 to 20db reduction in audio from zone to zone."

Four zones

image copyright Harman image caption The system uses algorithms to create a noise-cancelling effect

In practice what that means is that you still get a hint of what the other passengers are listening to, but it's very much background noise.

During the demo the car remains stationary, but Mr Ludwig said that were it being driven, the resulting noise would further dampen sounds passing seat-to-seat.

"We can achieve four different audio zones," he says.

"It could be that the driver wants to enjoy a sports game. His wife is sitting next to him, and she would like to have some soft music playing.

"And maybe you have kids in the back, and they want to watch [different] movies.

"It really gives you a way to listen to what you want, rather than having to put the driver in full control."

Directed navigation

There are other potential benefits too.

Even if the passengers want to listen to the same music they can each set the volume at a different level.

In addition, the driver can set his or her speakers to override the tunes with navigation prompts, while the other passengers listen to the songs uninterrupted.

Furthermore, if one of the travellers wants to make a mobile phone call, they can do so on loudspeaker without spoiling the others' enjoyment.

Experiencing the effect is surreal. To switch back and forth from loud commentators discussing a baseball match to the chords of a Bruno Mars track by simply moving one's head between the car's two front seats seems to defy past experience of how sound should work.

Harman has already branded the experience as ISZ - individual sound zones - and says it is ready to begin talks with manufacturers about building the tech into vehicles.

image copyright Thinkstock image caption The innovation could make driving holidays a more enjoyable experience

However, one expert downplayed the idea that this was a giant leap forward.

"This is more an evolution than revolution," remarked Seung Min Yu, an automotive analyst at Consumer Reports magazine.

"The just announced Audi Q7, for example, will have an optional 23-speaker sound system that uses software and microphones to adapt music playback to deal with other noises.

"And luxury cars like the Mercedes S Class and the BMW 7 series already offer Bluetooth headphone equipment for passengers in the back seats that link into their in-car entertainment systems."

The big question is how much extra car buyers would have to pay to add the ISZ tech.

Harman declined to provide an estimate, but it is unlikely to be cheap.

Even so, the BBC understands that at least one other company is looking to develop a similar technology.

And the more competition there is, the better the chance that such tech will become affordable over time.