In the audio world, there are progressive improvements … and ruptures. Most modern speakers are based on a centenary technology, that of the electrodynamic transducer: a mobile coil moves under the effect of a magnetic field generated by a magnet, vibrating a membrane to produce sound. A simple, effective principle, but which has reached its limits in an era where sound is always more immersive, while being integrated into ever more compact objects.
This is where intervenes Sound Motiona transduce technology developed by a Dutch start-up named Mayht and bought by Sonos in 2022. This system fundamentally rethinks the operation of a speaker. There is no longer any question of “making sound”, but to repel the physical constraints of audio design: miniaturization, energy efficiency, distortion control, management of internal pressures … So many challenges to which Sound Motion brings concrete responses. 01net.com went to the European premises of Sonos in Hilversum (Netherlands) to exchange with one of its designers.
A strategic acquisition
The story begins just a few kilometers away, in Utrecht. Founded by two passionate brothers, Matthias and Timothy Scheek, Mayht launched in 2016 with a simple but ambitious objective: managing to get a sound worthy of the greatest hi-fi systems of a small box. “What we were looking for was a way to condense audio performance in a much more compact volume”explains Naphur Van Apeldoorn, principal material in material development at Sonos, former employee of Mayht.
Over the years, the small team has developed a promising prototype, which it baptized “T3” in reference to its 3 -inch size. This new generation transducer, designed to be integrated into mass audio products, quickly attracts the attention of the sector. In 2022, Sonos acquired Mayht, convinced by the potential of this technology that the American company will then baptize “Sound Motion”.
“Three days after the acquisition, we were already in Santa Barbara, at the siege of Sonos, with a prototype on the table. The team told us: we want that, in this format. And there we understood the challenge “recalls Van Apeldoorn. The challenge was indeed to integrate these new speakers into the future ultra arc, without compromising its design, its performance, or its ability to be industrialized.
What makes sound motion unique
Sound Motion’s secret is in a complete overhaul of the architecture of transducers. Instead of a single electromagnetic engine placed in the center of the membrane, Sound Motion distributes the effort between four miniature engines positioned in the corners of the unit. Each engine is made up of two neodymium magnets in opposition, which generates an intense and controlled magnetic field without using a heavy metal structure. “The only thing we have kept from a traditional transducer is the rubber peripheral membrane. Everything else is unprecedented “Résume Naphur van Apeldoorn.
This configuration makes it possible to multiply the useful surface of the speaker to produce sound. Unlike a conventional transducer where only the central part of the membrane is mobile, here, it is almost the whole facade which contributes to the creation of acoustic waves. Result: three times more acoustic pressure with equivalent footprint, without generating more distortion.
The system is also based on a double membrane in opposition (Push-Push configuration), which allows natural cancellation of mechanical forces. This limits parasitic vibrations in the enclosure, stabilizes the structure and considerably improves audio rendering, especially in low frequencies.
New generation materials
Almost everything has been redesigned. The suspensions, traditionally made of glue coated fabric, are made here in injected polymer, according to a process from precision engineering. “We were inspired by the blade springs of the old horse -drawn cars to create more compact and more efficient suspensions”details the engineer. This change improves not only the longevity of the speaker, but also the precision of the movement.
Another example of optimization: internal cone reinforcements are made via aluminum ribs, designed by an optimized topology algorithm. Result: a reduction of 33 % of the mobile mass, while retaining the rigidity necessary to cash in very high internal pressures. The speaker can thus reach a total mechanical excursion of 18 mm (9 mm in each direction), which is enormous at the scale of a consumer product.
Efficiency, power and miniaturization
Sound Motion’s main advantage is not only in its raw performance. It is the efficiency that changes the situation. At equivalent acoustic pressure, a sound motion transducer is four times more compact and four times lighter than a traditional speaker. This makes it possible to integrate more units into the same product or to reduce the total volume of the enclosure without sacrificing the sound rendering.
This compactness also allows more efficient thermal management, reduced electricity consumption and greater freedom in the design of audio products. “With Sound Motion, we can design more flat, thinner or even on -board speakers in very small connected objects”Souligne van Apeldoorn.
The Sonos Arc Ultra, technological showcase
It is therefore in the sound bar ultra that Sound Motion makes its debut, in a rather discreet way, it must be admitted. Despite the scope of this innovation, Sonos opted for a rather sober communication. Some even regret the too generic name of technology. “The name Sound Motion does not say how revolutionary it is,” said a journalist present during the exchange. A reproach to which Naphur Van Apeldoorn responded with humor: “If your only criticism of our product is his name, then I sign immediately”.
But the choice ofArc Ultra is not trivial. Flagship model of the brand, this slender sound bar over a meter wide concentrates all of Sonos’ know-how. It has 14 transducers, including a Sound Motion subwoofer, redesigned mediums, tweeters oriented upwards and very advanced digital signal processing (DSP).
During our test, it was above all the depth of the bass and the precision of the central canal that had impressed us. Without an external box, the ultra arc manages to produce a serious, fast and impactful, thanks to the Sound Motion transducer. “Compared to the classic arc, we doubled the acoustic pressure at 50 Hz”says Naphur Van Apeldoorn. All in an unchanged format.
From theory to mass production
Going from prototype to industrial production was not an easy task. The first weeks after the acquisition were devoted to intensive tests, with more than 900 simulated digital models, more than 30 3D printed prototypes and series of continuous iterations. Each day, engineers produced, tested, modified.
“We manufactured one transducer a day, sometimes two. They were immediately tested to measure the answer, the distortion, the mechanical outfit. It is this ability to iterate very quickly that allowed us to converge on an industrial viable solution ”Raconte van Apeldoorn.
Sonos also used its manufacturing expertise to standardize the process, reduce variations between units and guarantee maximum reliability. Where the fabric suspensions vary from one lot to another, the components molded by injection offer an almost perfect regularity. So much so that Sound Motion transducers have less variation than traditional models.
A technology designed to last
Integration into the ultra arc is only a first step. Sound Motion is a modular technological platform, called to equip other Sonos products in the years to come. Portable speakers, bars of its most compact, multiroom systems, even on -board connected objects: the applications are multiple. Van Apeldoorn is also enthusiastic: “This is only the beginning. One can imagine even more compact, more powerful, more energy -efficient speakers. Anything is possible ”.
With Sound Motion, Sonos is not content to optimize his speakers : it changes the rules of the game. More than a simple improved speaker, this new generation transducer redefines what an audio product can accomplish in terms of performance, efficiency and integration. The ultra arc is the first concrete demonstration – and more than successful. But the real benefits of this technology will be felt in the coming years, as Sonos will deploy it in other formats. For the moment, only one thing is certain: now, our speakers will no longer be the same.
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