In December 2004, a small group of people heard for the first time the prototype D-TK10, the shape of which was close to being finalized. The group included, among others, the president of Takamine Guitars and an Onkyo planning and development representative. Although some aspects of the sound were still a little raw, it achieved a fascinating performance that couldn’t be found on other speaker systems. Their comments regarding the speaker were very positive, and gave us confidence about the potential of this product. We wanted this speaker to bear the name Takamine. Development of the speaker system originally began in June 2003, following a product planner’s idea that the body of a musical instrument might make a good model for a speaker design. Our focus turned to one of the more common wood-constructed instruments, the acoustic guitar. In the end, it was Takamine Guitars who accepted our request for a factory tour and technical advice. We relished the chance to work with such an outstanding partner—one renowned for its high-grade woodcraft and painting technology, its ability to combine hand-crafting and machine work, its dedication to manufacturing, and its passion for sound. The Takamine brand is a symbol of integrity and confidence in products that are made with pride.

We wondered about the potential of their guitars. Our first step was to listen to the sound of speaker units connected to an unpainted guitar provided by Takamine. What emanated was purely guitar-like in sound. Volume was generated by the whole body of the guitar. But from an audio standpoint, it was extremely poor in quality. We doubted whether this project would work. At that moment, everyone could see how difficult a challenge faced us. We realized that something needed to be done about this. What elements did we need to work out to make a speaker system that could cross the threshold and be seen as not just an audio component, but as a musical instrument? What elements are responsible for creating the notes that a musical instrument creates? Again and again, we made prototypes incorporating the elements in various forms. The structure of a guitar’s body is very simple. The framework, the shape of which can be determined from an anterior view, is made of curved wood. A thin plate fits into the anchoring materials, or “bracing,” on both sides of the frame (corresponding to the front and back). It is then put through the overlapping width, or “lining.” The bracing has as much influence on the musical notes from these components as does the thin plate. The sound will vary greatly, depending on the positioning and number of pieces, and on the shape of the components.

A box made from a thin plate wouldn’t be strong enough to bear a heavy speaker unit. It would be shaken by backward pressure and vibrations from the speaker unit. On the other hand, if the box were strengthened simply by increasing its thickness, the quality of the musical notes would be sacrificed. We sought a combination of body strength and the ability to produce musical notes accurately. Thus, we invented a frame which uses relatively strong curved wood parts like those on a guitar’s body. The top and bottom of the guitar’s protruding section formed the side panels of the speaker. The anchoring material was then inserted, followed by the speaker unit itself. By changing the bracing set-up, we were able to control the tone and broaden the sound as much as we wanted. We decided to use mahogany for the cabinet material, to emphasize the quality of the musical notes. We used a single plate for each side panel and a curved plywood plate from front to back and through to the bottom. Thus, the basic design was completed one year from the start of development. As we said at the start, this first prototype well and truly showed the potential of this product.

While the basic design had thus been agreed upon, the production process was still a battle against the clock. Since it took about a month and a half to construct and paint one cabinet prototype, we were unable to make multiple prototypes from scratch. After repeated measurements and auditions, though, we did manage simultaneously to create different versions of our basic prototype. We did this by varying the bracing layout, by adjusting the network and noise-absorbing materials, and also by adding bracing materials that we had made in-house. When it came time to review the second prototype (the technology prototype), we were reasonably satisfied with its sound quality. So we took it to Takamine Guitars for an audition. Their response, however, was typical of people dedicated strictly to the sound of the guitar. They preferred the first prototype. While the second prototype had a very high-quality finish for a speaker system— almost enough for it to be taken as an actual musical instrument—we had failed to achieve the appealing sound of which a real musical instrument is capable. This led us to revise our manufacturing goals. We wanted to be able to hear a greater range of notes, and at the same time to make the sound more polished. These desires were not part of our original concept for the D-TK10, and, given the tight schedule we were working to, we didn’t think we had enough time to follow through on them. To ensure they would be satisfactorily completed, we took an extremely painstaking approach to the construction of the speakers. There was some debate as to whether we should take a safe approach or a riskier one. After much deliberation, we decided to gamble in pursuit of perfection. We went to Takamine Guitars to seek help in enhancing the speaker’s features. At first, they showed grave concern over making major changes at such a late stage. Eventually, they offered suggestions about how to develop certain features of the speaker system, so that it could rightly bear the name “Takamine.” In the end, we agreed to change the board thickness and the bracing layout. These changes were duly incorporated into the pre-production model, and the cabinet was made following feedback from both Takamine and Onkyo staff. We had great expectations for hearing high-quality sound, but it didn’t turn out that way. We were at a loss as to what had caused the disappointing results. Everyone was quite perturbed. All we had done was make the board 0.5 mm thinner than on the last prototype, to aid the unit in creating a greater range of musical notes. We became keenly aware that the ideal bracing layout differs depending on the board thickness. So our next step was to make a painstaking search for places where the board lacked strength. Fortunately, we were able to solve the strength problem by adding a single bracing and by repositioning the noise-absorbing material. Meanwhile, we were able to generate a wider range of notes and make the sound more polished, which were our other key issues. This was sweet reward after we had pushed ourselves so hard in keeping to a tight pre-production schedule.

The key aspect of this product is the cabinet, but there are also many other features that we paid obsessive attention to, starting with the speaker unit. Both the woofer and tweeter were designed by computer simulation to operate in piston motion, with consistent movement across their surfaces. We weren’t sure whether the speaker elements would move like that or not in reality, but they seemed to move ideally in the simulation. The real answer to this question would come when we measured the vibration performance of the cabinet. Using a laser scanning sensor, we were able to confirm visually that the entire diaphragm was vibrating as one. This result gave us encouragement about our progress in developing the unit.

The pedestal section, which comprises a discrete bass-reflex duct, was made from rosewood. The shape and production method were determined in consultations between our designers and a local manufacturer. The pedestal was made more compatible with the cabinet body, which could then simply be placed on top.

Furthermore, the speaker did not feature a protective grille, a standard feature of conventional speaker systems. This was a controversial issue, but we persisted in our belief that to hear good-quality sound, there is no need for a grille. Instead, we included a cover to attach to the speakers when they are not in use.
December 5th 2005 was the first day of retail sales for the D-TK10, the world’s first speaker to share design characteristics with an acoustic guitar. Because the manufacture of this audiophile speaker is highly labor-intensive, monthly production is limited to 50 pairs. Proudly displayed on the back of this speaker, the Takamine logo is proof that we met the challenge of proving the quality of Onkyo technology to a company from another industry—in this case a world-renowned guitar manufacturer.
People who listen to music from this speaker are usually surprised at the contrast between its small size and the amplitude of its sound. We developed this product with the desire to make it like a musical instrument—so the user could enjoy literally “playing” their music on it. All of us involved in creating this instrument give it our highest recommendation and sincerely hope you will enjoy playing your music on it.