For the past hundred years, audio reproduction has been based around the same principles. This, however, could be about to change thanks to new technology from Israel. Kate Jordan explains.

Basic loudspeakers have been in use since the 1880s. Since then, the basic mechanics of sound reproduction have remained largely the same. Apart from improvements to the materials and housing, the fundamentals of loudspeakers haven’t changed much in nearly a century.

In the same period, sound recording has undergone massive changes and developments, most importantly the move to digital. Sound reproduction, though, appears stuck in analogue – but that could be about to change.

Audio Pixels is an Israeli company (now wholly owned by an Australian company – more on that later) that has been working on developing digital sound reproduction technology. Audio Pixels chief executive Danny Lewin labels the development a ‘long overdue evolution’ in sound reproduction.

“Traditionally, an analogue speaker takes the analogue signal and oscillates at the desired frequency. If you’re trying to reproduce 15kHz, it’ll oscillate at 15kHz. It’s a single membrane trying to generate the pressure needed by moving a volume of air,” Danny explains.

“We do something very, very different. We have an array of ‘little speakers’. Each one contributes a pulse of acoustic energy and it’s the combination that creates the soundwave. That allows us to do a number of things differently using a far more compliant transducer to create the desired pressure.”

The theory behind the product is not new. The technology that makes it possible is called digital sound reconstruction (DSR), a technology theorised by Bell Labs in the late 1930s, but needed the advances in micro-electronic mechanical structures (MEMS) in the 1990s to make it possible.

MEMS technology is so small it’s measured in micrometres (a thousandth of a metre). Generally, MEMS chips contain some mechanical functionalities that allow the micro-electronics to interact with their surroundings – in the case of the Audio Pixels products, to move air to generate soundwaves.

“There’s a lot of talk about our single chip, but the chip can then be cascaded into larger arrays. That is essentially how we reach any application. We’re talking everything from public address systems all the way down to the smallest of devices,” Danny says.

What has gotten people so exited is that the innovation offers improved sound quality in a smaller, more energy-efficient loudspeaker. Any device containing a speaker could be shrunk and then run for a lot longer on the same battery.

“It’s certainly exciting to get up every morning,” Danny says.

“Most technologists spend their careers making some sort of incremental improvements to existing technologies. Here, we’re breaking down barriers. The ability to change future generations of devices and improve them is very exciting.”

The stock market agrees. Audio Pixels is now wholly owned by an Australian company of the same name and listed on the Australian Securities Exchange, where it is one of the big movers in an otherwise flat audio market. From January 2014 to the following September, Audio Pixels’ shares increased 275% to $14.50. The price has fluctuated a little since then, but has remained high.

Given the benefits offered by the technology, this is hardly surprising – except that Audio Pixels is yet to release a single product. It’s still in the design and development stage.

In March, Audio Pixels finished phrase three of development and passed the required testing with flying colours. It’s now into the fourth – and final – phase of testing. There’s no definite date for completion; being a fabless semiconductor company, Audio Pixels relies on third party vendors to produce its products. With MEMS technology still being relatively new, there aren’t many companies who can assist and the technology to make these products is still itself being developed.

“It’s not like the traditional semiconductor industry where if you have the equipment, the reproduction is fairly predictable. This is still an evolving science, because you’re building a three dimensional structure that is not the same as another three dimensional structure,” Danny says.

There’s no definite timeline on when we’ll see Audio Pixels audio chips in products and the resulting impact they’ll have on the audio industry. But Danny does have some words of encouragement:

“We’re working hard, we’re on the road, and we can see the light at the end of the tunnel. It’s just a complex technology that requires time.

“If everybody’s patient, we’ll deliver.”