For the A4000 to achieve the impossibly high-quality sound for this price range requires new development and production facility. The 6mm diameter dynamic driver requires not just new parts, but a total redesign of everything, including the production machinery. Sound design was conducted based on our proprietary sound evaluation method established during the development of our flagship A8000 model. It achieves “transparent sound”, which means an impression that even sound images localized distantly can be heard clearly, for various genres of music.

The development of the A series began with the establishment of a new sound evaluation method by analyzing the relationship between sound quality and physical characteristics. The results came to fruition with the A8000, and the sound evaluation method evolved further with the A4000. We listen to music recorded at various qualities at various sound levels. Conventional evaluation methods, however, generally entail a subjective evaluation under the fixed conditions such as constant sound pressure level , and an evaluation method that takes into account the various pratical listening conditions that could actually occur when users evaluate the sound of various products of earphones didn’t exist. We believe that researching a sound evaluation method that made it possible to arrive at a realistic evaluation even under various different listening conditions made it possible to bring to fruition a product that can be said to be the new standard for this price range.

In order to achieve sound quality impossible at this price range, we newly developed 6mmφ [f-Core DU] dynamic driver unit from the scratch. To realize the brand new driver, we established new production facility overseas and newly designed not only parts for the driver unit such as diaphragm, voice coil, magnet, magnetic circuits, adhesives, but also the production machinery used in the manufacturing process. As material for the driver front housing, rather than the traditional aluminum, we used brass, a material that is both highly resistant to the effects of magnetism and also boasts a high specific gravity. In order to increase the time response characteristic of the diaphragm, the voice coil employs a 30μ ultrathin CCAW, and a minimum of adhesive is used for assembly to thoroughly lighten the moving parts. Moreover, the diaphragms are neatly pressed in small lots of roughly 1/3 the normal size in order to constrain pressure deviation to a minimum and realize uniform shaped diaphragm with no deformation.

Based on the chassis design that serves as an ideal solution for the IEM that become established during development of the B Series, the A4000 realizes a superior sense of fit. Whether or not earphones offer a superior sensation of fit is determined by the sensation of oppression. While at first glance it may seem correct to select an ergonomic shape and hold it in place with the elasticity of silicone, this always places pressure on the ear which creates an unwary burden and leads to the accumulation of fatigue. By limiting the area that comes in contact with the ear in contrast to an ergonomic shape that comes in contact with a large area of the ear, this product aims to achieve a sense of fit with no feeling of oppression. The green section of the diagram below (earpiece) is the 1st position, the blue section (Tragus) is the 2nd position, and the pink colored section (cavity of the concha) is the 3rd position which contribute to the ultimate stablity and fitting. For that reason, it is suitable for the ears of many different people. To the extent that there is no feeling of oppression at any of the points of contact, that makes for such a comfortable, superior feeling of a customized earphone fit.

The 2-Pin connector is a high precision part that was developed in-house. The plug employs the highest versatility φ0.78 standard. The cable employs soft, supple coating material designed with consideration to touch noise and bends flexibly when used in conjunction with an ear hook to achieve a good fit.

An ear hook is effective in reducing touch noise; wearing it when walking dramatically reduces the unpleasant rustling sound that may occur when the cable rubs against the body (cable touch noise). In the past, our company’s ear hooks have characteristically been slimmer than ordinary and virtually indistinguishable from a wire or rosin filled cable, making it so comfortable that it is easy to forget that one is even wearing it. This is the type with an affixed lock (B Type) that is capable of holding the cable firmly in place.

Two types of silicon differing in rigidity are employed for the sound conduit and for the earbud that comes into contact with the user’s ear. The silicon used for the sound conduit is more rigid than that used for the earbud, and by having groove processing applied to it, combines both strength and flexibility. Soft silicon has been employed for the earbud, making for a comfortable fit and a high level of sound insulation.
One of the bushes is gray, while the other is red; by pulling the earpiece back slightly to check the color of the bush, it is easy to distinguish between left and right, even in places with subdued lighting. Since the bush colors of neighboring sizes are different (the gray bushes alternate between dark and light gray; the red bushes alternate between red and pink), it is also easy to distinguish between sizes.

With this silicon carry case, the cables can be rolled up and stored easily. The earphones themselves are gently secured using thin dome-shaped silicon covers.

Aging refers to the phenomenon whereby the sound produced by the earphones changes over time as they are used. There is a small driver unit – what could be called a speaker – inside the earphones; a diaphragm of extremely thin film is attached to this using a coil and an adhesive agent. With aural signals, the diaphragm moves in micronic increments while the coil moves, giving off sound. While it can’t be proven, we believe that in this situation, the adhesive section may possibly influence these infinitesimal movements. Using the product over a set period of time, the diaphragm moves more easily, and sound quality approaches the original design intent. This product has a small aperture, and so an extended period of time is necessary for changes through aging to become indecipherable. In general, if the product is used in a normal way over a period of 150 ~ 200 hours, it should feel that sound has become more subtle. A more favorable outcome can be obtained through aging of the product by listening to the music you normally listen to at a volume you usually listen at, rather than expediting aging through very high volumes or aging through noise. While not an accurate metaphor, when you make unnecessary movements to break in a pair of shoes, you’re bound to cause wrinkles different to those that occur when you walk normally. In the same way, rather than having the diaphragm move unnecessarily, it is better to think that it is more natural to break it in in the environment in which it is used.

There is also a psychological aspect to aging. Buying a new set of earphones, the impression you had of these earphones prior to buying them is by no means set in stone. You’re actually making a relative comparison between these and the earphones that you use on a daily basis. When you buy a new set of earphones and continue to use them for a set period of time, those earphones become the standard. An evaluation of sound quality based on continuing to use them until they become such a standard makes it easier to choose a product that you don’t get tired of over the long term.

Silicon carry case, Ear tips, Ear hook TYPE B

This product is an earphone that is hung over the ear. The transmission of touch noise to the ear can be prevented by placing the cable on the ear to achieve a comfortable fit.
STEP1 Confirm the R and L marks on the inside of the chassis. R is right, and L is left.
STEP2 Run the cable toward the front from behind the ear, and insert the earpiece of the earphone into the ear.
STEP3 If it is difficult to fir the earphone into the cavity of concha, try to insert the earphone while pulling back and somewhat upward on the ear lobe.
* If the cable does not fit on the back of the ear, please use the ear hook accessory.
* If the fit is too loose, try changing the size of the sleeve. In some cases, the size of the left and right earpieces may be different.

Each sound is extremely clear, and because the rising of sound is good, the timing of vocals and instruments can be perceived quite clearly and the rhythm can be heard distinctly. For that reason, you can enjoy a greater emotional uplift from music than before, and even a familiar playlist can serve as a source of new inspiration.