1000X series Developer Interview

Introducing three fine wireless noise-canceling models from Sony

―The 1000X series now has three new models. Tell us about the overall series concept.

Ohba: Last year's MDR-1000X was our acclaimed flagship wireless model that won many fans. WH-1000XM2 is a successor headband model, but even during MDR-1000X development, we hoped to create wireless noise-canceling earbuds one day that would be compact and easy to carry. In fact, because Sony has excelled at wireless transmission and noise cancellation for some time, we'd always planned to expand these technologies to styles besides headband headphones.
That's why we developed three styles this time, including WI-1000X in-ear neckband headphones and truly wireless headphones WF-1000X, because the truly wireless market is now getting focused on as the new style.
Combining these Sony technologies, we set out to bring people different styles, each with industry-leading noise cancellation.

―In the 1000X series design, what aspects of the new headphones stay true to the original MDR-1000X concept?

Kumano: What we imagined when developing the original MDR-1000X was a design that made you glad you owned them. They'd be a treasured possession you'd also want to bring on trips, for example. Most users seem not to show off their things to others, but do care a lot about their things. We also wanted these advanced wireless headphones to become a part of your other possessions smoothly. That's also one reason we added the champagne gold color option this time.
Now you can choose from three styles of headphones in the 1000X series. In all three, we focused on how the design could convey the excellent noise cancellation and sense of innovation originally achieved with the MDR-1000X. It was challenging, but we struck a good match with series textures and colors and stayed true to the original 1000X image.

―How does the new WH-1000XM2 improve upon the original MDR-1000X?

Ohba: Besides the many subtle refinements you'd expect, two major differences are noise cancellation that adapts to changes in atmospheric pressure and compatibility with our mobile app.
First, the noise cancellation is now optimized for your current atmospheric pressure. We introduced this feature with business travelers in mind, thinking that on flights, they would appreciate noise cancellation under slightly more ideal conditions.
On a flight, changes in air pressure-specifically, changes in atmospheric density-affect how sound travels between the driver unit and your eardrum.
Without some adjustment, these changes in sound propagation prevent optimal noise cancellation.

This model has a built-in atmospheric pressure sensor that detects changes in ambient pressure. Noise cancellation processing is adjusted for optimal processing under the current pressure, which enables ideal noise cancellation where the atmospheric pressure changes.
App support was also added. One big advance here is ambient sound control. In Ambient Sound mode, you can adjust how much outside sound the headphones pick up. One scenario where this is convenient is when you're listening to soft classical music, for example. Too much ambient sound makes it hard to hear the music and interferes with listening, but you can adjust the level to suit the environment and your tastes. So now, you can freely control how much ambient sound is picked up, to match the music and listening environment. Another feature, called adaptive sound control, switches to the optimal ambient sound control settings automatically, based on your detected activity-whether you're still, walking, running, or riding in a vehicle. This way, you don't need to switch modes yourself each time, and it's easier to just enjoy listening. In the app, you can also set up the surround effect and equalizer, so you can listen with your preferred soundstage and tone. App features vary by model, but you can use the app with all three of the new 1000X models, so it's a highlight of the series.
WH-1000XM2 headphones also have further refinements to internal processing over the original MDR-1000X. In fact, battery life is nearly four hours longer.
For up to nearly ten hours more of battery life, you can turn off DSEE HX signal processing from the app, which you can't do for the MDR-1000X. This brings total battery life with noise cancellation to approximately thirty hours of continuous playback at maximum.
Total battery life for MDR-1000X was about twenty hours, so we managed to add features while keeping power consumption under control.

WI-1000X-noise cancellation rivaling full-size headphones in a compact neckband model

―First, describe the basic concept of WI-1000X neckband headphones.

Ohba: It all began with wanting to bring the industry-leading noise cancellation of MDR-1000X to smaller headphones that are perfect on the go.
Popular styles of headphones vary around the world, but in Japan, many commuters listen to music, and most prefer earbuds. We imagined what these listeners, maybe in their 30s, might want to use every day. There's still some resistance to seeing people in suits wearing full-size headphones, but we knew no one would hesitate to wear an in-ear model.
WI-1000X are in-ear neckband headphones. This style of headphones resembles h.ear in Wireless (MDR-EX750BT), released in March 2016. People liked the convenience of just keeping them around your neck when you're not listening, so we took the same approach for WI-1000X.

―WI-1000X offers the highest class of noise cancellation in the industry despite being in-ear headphones. How did you manage to do this?

Tobise: Several things made it possible, but one is dual noise sensor technology.
Two mics pick up the noise to cancel. A feedback (FB) mic picks up noise between the driver and your eardrum. Outside noise is picked up by a feedforward (FF) mic. Together, these help the digital noise-canceling circuit generate a high-precision signal to counteract the noise.
The FB mic focuses on feedback cancellation by picking up and reducing noise in your ear canal, while the FF mic focuses on feedforward cancellation of external noise. Combined, they provide superior noise cancellation across a broad frequency range. To offer the industry's highest level of noise cancellation in this model, we had to use dual noise sensor technology.
It was challenging to arrange these two mics in small in-ear headphones, where space is limited. Working with our mechanical design engineers, we created and assessed a series of prototype bodies until we had an optimal structure-small, but offering maximum noise cancellation.
This level of noise cancellation required more than structural optimization of the headphone section, though. It was essential to get overall system design right, including the electric circuit. All of us on the development team had to talk it out as we moved ahead.

Shinohara: To cancel strong low-frequency noise, you need an amp with a large output stage, as well as a low-latency processor, among other things. That's why it needed exactly the same system as in MDR-1000X-a fully digital S-Master HX amp, balanced output, and a digital noise-canceling circuit. This combination of an improved S/N ratio from S-Master HX, crosstalk and noise improvements from balanced output, and ultra low-latency signal processing from the digital noise-canceling circuit enabled the industry's highest class of noise cancellation.
Still, it was very tough shrinking a system originally developed for MDR-1000X to this size.
Without the perfect board layout and pattern design, S-Master HX performance could never reach its full potential. We spent a lot of time after presentation of the initial design studying board layouts with MDR-1000X development members, designers, and mechanical design engineers.
Our highest priority was audio quality and noise cancellation, but we also had to ensure good Bluetooth antenna performance. Conceptually, we took the same approach as for MDR-1000X, but we ended up with a completely different board pattern. After several attempts, we had a layout that maintained both noise cancellation and antenna performance.

―WI-1000X uses an HD hybrid driver system, as found in XBA-N1. Tell us a few details about the driver, which probably provides the same high performance for those earbuds.

Tobise: As in XBA-N1 and XBA-N3, WI-1000X uses an HD hybrid driver system that combines a 9 mm dynamic driver with a balanced armature driver. The balanced armature driver is the same as in XBA-N1 and XBA-N3, but the dynamic driver is different, though still 9 mm. Noise from bus or jet engines carries a lot of low-frequency energy, and canceling it requires a driver that's very responsive in this range.
Earbuds from h.ear in NC (MDR-EX750NA) feature a 9 mm dynamic driver with excellent low-frequency response. We paired this dynamic driver, which excels at noise cancellation, with a balanced armature driver designed for superb audio quality. It's quite an impressive combination. Together in the HD hybrid driver system, they offer both exceptional sound and effective noise cancellation.

―It looks like WI-1000X is ready for high-resolution wireless listening. As with WH-1000XM2, it supports the advanced LDAC codec and features DSEE HX signal processing.

Ohba: More devices than ever will be supporting LDAC, whether from Sony or others, now that Android O has built-in codec support. These headphones also introduce aptX HD compatibility.
As Bluetooth headphones take off, people will need to connect them to their device using a codec designed for the best audio quality.

Shinohara: To offer high audio quality, as mentioned, it's a key point that WI-1000X uses S-Master HX and balanced output.
S-Master HX excels at playing music from LDAC or other high-quality codecs with exquisite resolution, presence, and soundstage. Balanced output also contributes to higher audio quality by eliminating crosstalk between channels and reducing the effect of noise. It was suggested during development that the neckband might look better if we went with unbalanced output, which would allow smaller boards inside. For this product, though, we were unwilling to compromise on audio quality. Working closely with our designers, we succeeded in incorporating both S-Master HX and balanced output.

―What special measures did you take for WI-1000X design and comfort?

Kumano: This style rests around your neck, so we wanted to keep the neckband slim. But as mentioned, for this model, we couldn't compromise on audio quality, so slimness wasn't our only goal. Everyone contributed as we worked toward audio quality and usability, until finally, we had everything just the right size.
What proved tricky was the part made of stainless steel, which curves three-dimensionally when viewed from the side. Initially, some of us thought it would be too difficult to make. It took repeated attempts by our mechanical design engineers to perfect the steel fabrication.

Yamamoto: It looks like an uninterrupted steel band, but that would block the antenna and affect reception. That's why fabrication actually involves two steps, with plastic near the antenna to let signals through.
Also, although they're neckband headphones and smaller than MDR-1000X, for uncompromising sound we had to incorporate equivalent power components. To do it, we revised the board layout and shape of the previous model, but making it smaller was quite a feat.

Kumano: In the earbuds themselves, there's a sophisticated arrangement of dynamic driver, balanced armature driver, and two mics. It took some effort to wrap them up in a sleek band with appealing textures.
The neckband housing is made of a soft material. This keeps the texture smooth, with buttons seamlessly integrated into the body.
Also, you can store the cables in the groove along the edge of the band.
The earbuds are near your ears when you pull them out, and they're less likely to become tangled, which makes this shape very convenient.
It was a bright idea from our designers.

Yamamoto: XBA-N1 and XBA-N3 have two drivers in the housing, but WI-1000X also includes two mics for noise cancellation. Still, we couldn't sacrifice comfort as a compromise for adding the mics. Some diligence on our part led to a secure, comfortable fit.

WF-1000X - truly wireless headphones with leading noise cancellation that free you from stress of all kinds

-Few truly wireless headphones have noise cancellation. How did you succeed in offering both in WF-1000X?

Ohba: Many "wireless" headphones have the left and right earbuds linked by a cable. At Sony, a lot of us thought we should be able to make truly wireless headphones with no cable at all. As the wireless era began for us and other manufacturers, we set out to develop truly wireless headphones. Among the things we discussed was whether to include noise cancellation or just make regular wireless headphones. Noise cancellation in MDR-1000X was a hit, so many of us were eager to include it.
One goal in WF-1000X development that didn't really apply to the other headphones was to create the kind of stress-free experience only possible with a truly wireless model.
Audio quality was a priority, of course, but there would be no noise or cables to deal with, and adaptive sound control would eliminate the need to switch noise-canceling modes manually. That's three things you don't need to worry about. Even compared to other 1000X headphones, these would be minimalist. From the first planning stage, our success would depend on how much we could pare down the element.

Sasaki: A key point in this headphone style is improving antenna characteristics through wireless performance. Structurally, we considered a few options at first, including clip-on and behind-the-ear headphones, before we settled on a shape where antennas could be arranged without being affected much by individual differences in ear shape.
Initially we had a feeling it would be impossible to fit everything in such a small body. Each earbud is independent, so the right and left buds include their own Bluetooth module. We had to diverge from past products by considering how to make headphones with as few internal components as possible. At the same time, we could not compromise on audio quality. Many parts are used, but we chose the most advanced and compact. The driver itself was also newly developed.

―Developing the new driver must have been challenging. What were the other difficulties you faced to offer such high audio quality in such a small body?

Tobise: WF-1000X features a new 6 mm dynamic driver. For outstanding noise cancellation in such a limited space, the driver had to be small and have excellent low-frequency response. Through an optimal diaphragm shape (determined with original simulation techniques) and a magnetic circuit with an external magnetic path exhibiting high driving force, we created a small, 6 mm driver with ample low-frequency response.

Sasaki: Electrically, we had to reduce the noise that circuits inevitably generate. One source of noise is around the power supply. In a larger body, we could add a capacitor to reduce some noise, but in headphones that had to be small, it wasn't so easy. Innovative engineering in the circuit pattern and layout helped reduce the noise as much as possible. This took repeated testing, because we didn't know about any noise until we listened.
Each earbud has its own battery, which required a little ingenuity in the charging case. Charging generates some heat from current flowing in the circuit. Optimization to keep the small earbuds cool included adjusting the battery and NFC antenna layout, with help from our mechanical design experts.

-What enhancements improved style or comfort?

Kumano: A good fit is clearly important. Many components are mounted internally, so it took much effort to design the layout with comfort in mind.
Fitting supporters hold the earbuds steady in your ear. We wanted to keep them small, so you can leave them on during charging. The fitting supporters nestle against the inside of your ear and hold the earbuds in place, once you insert the earbuds and turn them to face downward slightly. It took many prototypes to decide on the best design.
While maintaining a sense of consistency with the 1000X series as a whole, we sought refined textures and the allure of something fashionable, which we tried to balance with the innovativeness of truly wireless headphones. Body surfaces look relatively smooth. We call this Single Shape design.
Once everything fits in the tiny body, of course, the earbuds must also fit in your ear. To perfect the internal layout, we met again and again with our electrical design team.
One tricky aspect of the design was the loop visible though the clear plastic portion, which is actually an antenna.
In a body that looks fairly solid and unified, moving the antenna forward not only improves reception, it adds a design accent.
The clear part also doubles as the LED indicator lens.
In the past, antennas have been a part we grappled with at the final stage of design, but in a product like this, a stable connection is everything. That's why we carefully monitored this aspect of design from the very start. I'm glad it also provided a nice design accent, in the end.

And that's how the highly acclaimed performance and features of MDR-1000X - the original flagship of Sony wireless noise-canceling headphones - have evolved into three styles of 1000X headphones to satisfy many tastes and listening styles. They're sure to catch the eye of many headphone fans.