Audio-Technica x Phile-web Tie-Up Event — Special Interview with the Engineer
The Development of Audio-Technica's CKR Series
— In-Ear Headphones with Drivers that are a World's First
Interviewer: Naoki Nakabayashi   Editing: Phile-web Editorial Department
Audio-Technica once again pioneers a new realm of in-ear headphones. The ATH-CKR9 and ATH-CKR10, the two high-end models in the CKR series of in-ear headphones, feature the world's first* "DUAL PHASE PUSH-PULL DRIVERS." They are ambitious models that completely change the sound of in-ear headphones. How were these world's first drivers developed? What is the strategy that runs through these five models, all with different features? Key persons at Audio-Technica tell their story.
Persons in charge of CKR development and planning
Hiromichi Ozawa (right)
Manager, Engineering Headquarters Engineering Department Division 6
With 24 years of experience, Hiromichi Ozawa is the key person in sound engineering at Audio-Technica. He was in charge of developing some of the company's standard product lines including the AD series open-air dynamic headphones, as well as the CKS and ES series of in-ear headphones.
Hiroaki Kokubun (left)
Consumer Product Planning Division
Hiroaki Kokubun is in charge of the product planning for the CKR series. He has been in charge of the planning for various products including the WS models of the "SOLID BASS" series.
Naoki Nakabayashi (left)
Naoki Nakabayashi is involved not only in the field of audio/visual but also in a host of other industries and media. In addition to over-ear headphones and in-ear headphones, he is knowledgeable about music including jazz and roots music. He strives to provide reviews from both the hardware and software points of view.
Yuki Hirano (right)
Yuki Hirano is the editor-in-chief of Premium Headphone Guide, a free magazine that is distributed at electronics retail stores across Japan. He launched Premium Headphone Guide Magazine last year.
The CKR series originated from a desire to
"do something new."
Nakabayashi : On April 25, Audio-Technica released the CKR series, featuring the world's first* DUAL PHASE PUSH-PULL DRIVERS. The series has already drawn much attention, but how did it come about?

Kokubun : Planning for the CKR series really started to take shape about a year ago. The CKR series is the successor to the CKM series, which has been popular so far. From around 2011, we began talking about what we should do next as we launched the ATH-CKM1000, the third-generation flagship model of the CKM series. We didn't end up making significant changes then, but we were constantly looking for new topics and features that would surprise the world. I consulted Ozawa too, expressing my interest in working on something new. We came up with a number of ideas but they all lacked true patentable impact. Then I asked him, "What would happen if Audio-Technica produced models that feature hybrid or dual drivers that other companies offer?" This is eventually what gave birth to the CKR10/CKR9.

Ozawa : It is our job to always have a variety of ideas. With dual drivers too, we had been making prototypes for about three years. This is around the time when other manufacturers started to launch models with dual drivers. Those drivers, however, move in phase with each other, which increases distortion. So we designed a system in which the distortion problem is resolved by arranging the drivers to face each other and move in opposite phase while improving the magnetic flux. This eventually became the DUAL PHASE PUSH-PULL DRIVERS.
Five unique models developed under a consistent philosophy of "how best to enjoy music."
Nakabayashi : The CKR series consists of five models, with the ATH-CKR10 as the top-of-the-line model. Their price range as well as structures are quite different. What was the base concept for the planning and development of the series?

Kokubun : The top-of-the-line model, ATH-CKR10, costs 40,000 yen before tax. In contrast, the entry-level class ATH-CKR3 is 3,500 yen pre-tax, an affordable price. There are also models with an in-line mic and remote control for iOS devices and smartphones. We offer a wide-ranging lineup to accommodate different users economic condition.
All models are developed under a consistent philosophy of "how best to enjoy music." Our aim was to develop in-ear headphones that didn't over emphasize bass, but mid- and high-frequency clarity, allowing users to enjoy "true sounds." The "R" in CKR is derived from "Resolution," "Sound Reality," and "High Response." Ozawa is in charge of checking the audio on all models.
First, the high-end ATH-CKR9 and ATH-CKR10 models feature the world's first* DUAL PHASE PUSH-PULL DRIVERS. The ATH-CKR10 in particular is constructed with titanium housings and drivers with pure iron yokes, which are materials used for Audio-Technica's high-end models. We were also particular about the wire used to conduct signals. We used the star-quad stranded wire, a wire that is also used for models such as the ATH-CKW1000 and ATH-CKM1000. The ATH-CKR9 is a variant of the ATH-CKR10 and embodies the same philosophy but with aluminum housing.
The ATH-CKR7 and subsequent models feature full-range dynamic drivers and not the DUAL PHASE PUSH-PULL DRIVERS. All of these drivers were developed specifically for the new models.
The ATH-CKR7 features large-diameter 14 mm drivers, hybrid housing that combines machined stainless steel and aluminum, and high- and low-frequency acoustic resistors for frequency correction. It is a model that incorporates all the mechanisms of the single driver system that create outstanding sound and that have been adopted in previous models, including the CKM series flagship models. We are very pleased that we managed to make this model as affordable as 15,000 yen, pre-tax.
The ATH-CKR5 and ATH-CKR3 are accessible models in an affordable price. They are designed with larger drivers compared to other products in the same price range. They are also equipped with brass rings that reduce resonance, making them models that were engineered to offer superior sound. The ATH-CKR3 in particular is the outcome of our pursuit of a compact body without compromising sound quality.

Nakabayashi : The fact that Audio-Technica developed a wide range of unique models and launched them all at once shows the company's determination, drive and spirit. You didn't consider staggering their release dates?

Kokubun : We wanted to make an impact in the market this time around. In order to do this, we thought all the models had to be launched at the same time. Well, it's easy for me just to say so, but I'm sure it was incredibly troublesome on the production side (laughs).

Ozawa : They asked me if we could release all the models on April 25, so I said, "Sure, we can!" But in the back of my mind I was thinking, "Can we really?"