Interview: Mitsuru Hosoo, Final Audio Design

Hi-Fi+: How did you become interested in headphone (and earphone) design in the first place? What attracted you to this product category?

MH: When I was a child, I thought the Pioneer SEL40 we had at home was beautiful. So, Final’s headphone designs are influenced by this. I learned the joy of listening to really loud music with headphones. I remember being really surprised at there being a lot of sounds – such as the back chorus – that I couldn’t hear through speakers.
 

Hi-Fi+: As you work to create new top-tier headphone products, what are the top design objectives you try to bear in mind?

MH: I believe that what is most important is whether or not your emotions are stirred when you listen to music. I always see to it that my technical knowledge and experiences don’t hinder my responses.
 

Hi-Fi+: What technologies and product configurations best enable you to meet your design objectives?

MH: The precise form of the diaphragm. The coil and the diaphragm are joined together with great precision. At our company, we believe that controlling such essential basic techniques is important. It’s not possible to achieve your objectives just by sourcing and assembling cheap driver units on the market.
 

Hi-Fi+: Do you favour particular types of drive units for use in your designs and, if so, why?

MH: We don’t favor any particular type of driver. At present, we’re using BA (Balanced Armature) types and dynamic types, but we think that adopting the fruits of technological innovations of recent years is sure to bring about good results, and we’re currently investigating new types of driver units.

Hi-Fi+: How would you describe the ideal voicing ‘target curve’ for a headphone?

MH: Frequency response is the most important measurement, and we place emphasis on this. On the other hand, we think that placing emphasis only on sound quality frequency measurements is problematic. I hesitate to discuss frequency response here.
 

Hi-Fi+: What do you consider your top one or two product design achievements thus far? What makes those products special from your point of view?

MH: First, I would mention our Sonorous X headphone. This is a new product we’re planning on releasing at the beginning of summer this year. The distinctive features of this product are its light, strong titanium diaphragm, its strong magnet, and its front baffle and driver unit cut from aluminium in an integrated machining process. Unnecessary vibrations are reduced with the housing, which has been machined from a mass of aluminium, and through powering the light, strong diaphragm with a strong magnet. At the development stage of this model, we realized that combining the points above, which were right in theory, made for good results. The key points in creating a better quality product were the decisions to produce the important parts in-house, and to have the office and the production line for high-class items in the same place.

Second, I would mention our Piano Forte-series earphones. Piano Forte 8, 9, and 10 don’t use ear pads or ear tips. Not sealing the ear canal with an earpiece enables a natural acoustic feel to be achieved. We are currently researching extending bass tone audio bandwidth while maintaining this acoustic feel.

Hi-Fi+: When you listen for personal enjoyment, what types of music do you enjoy?

MH: I listen to all kinds of music, from classical to jazz, rock and electronica, but I particularly like listening to live recordings at a volume you would hear live music.

Hi-Fi+: What do you think the high-performance headphone marketplace will be like five years from now?

MH: I think perhaps it will be divided into wireless headphones and high-quality sound headphones. I believe that convenient wireless headphones with better sound than those at present will become common, but high-quality sound headphones will remain as items of particular interest for those with a fondness for such items.

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