Interviewer: Naoki Nakabayashi   Editing: Phile-web Editorial Department
The desire to have audio from in-ear headphones sound
as good as that from over-ear headphones.
Nakabayashi : What was the sound you were aiming for when you were developing the ATH-CKR9 and ATH-CKR10?

Ozawa : This is something I always thought. I think in-ear headphones still have room for improvement compared to over-ear headphones. So I feel it's my mission to render the sound of in-ear headphones closer to the clear and powerful sound of large driver over-ear headphones. Of course there's a limit to this because of the weakness of diaphragms...
In this respect, with the ATH-CKR9 and ATH-CKR10, I believe we managed to achieve audio that is similar to an over-ear headphone and much better than a conventional in-ear headphone.
With these models, we paid careful attention to not only the external design, but the packaging as well.
The product boxes are designed to fit tightly so that they won't slide off easily.
Hirano : Another characteristic is lower harmonic distortion in order to improve low-frequency response control.

Ozawa : Yes. Low frequencies are normally achieved with amplitude, but with Audio-Technica products, low-frequency sounds are reinforced while reducing the amplitude of diaphragms by designing the front and back of the driver unit to be as close as possible to being airtight. We believe this is the most effective design to reduce harmonic distortion.
Additionally, the CKR10, 9 and 7 feature bass acoustic resistors, which adjust low-frequency sounds. The mounting position and other conditions differ depending on the model, but the idea is the same for all models.

Nakabayashi : Is there an audio source that you always use to evaluate the audio?

Ozawa : Well, I've been listening to the same piece for 20 years... It's Mozart's piano sonata played by Ingrid Haebler. Over-ear headphones and in-ear headphones struggle with expression as the scale descends, especially in low frequencies. This is what I focus on.
External design that strikes a balance between audio and fit.
Hirano : Considering the ATH-CKR9 and ATH-CKR10 feature the drivers with a mechanism that is a world's first, I assume it was also a difficult task to decide on a design.
Kokubun : As for the design, we thoroughly discussed it with our designers, face-to-face. On the other end of the spectrum from the CKR series is the SOLID BASS series. It has an aggressive design and the audio is also designed for young people. On the other hand, with the CKR series, we aimed for something "standard" but innovative, so the designers struggled to translate the vision into a design.The housing inevitably gets bigger when there are two driver units to hold, so we went through some trial and error to figure out how to fit it in the ear. We made a series of adjustments both before and after the completion of the production mold, all the way up to the very last moment where we could still make the product launch date.

Nakabayashi : The more materials you add, the better the audio gets, but the more uncomfortable it gets to wear the product. I'm sure it was extremely hard to find the right balance between audio quality and fit.