In 1987, a design was introduced that allowed for smaller enclosures and extended playback time. A structure was created that balances portability and usage time.
D-30
The D-30 is a mid-range portable built on the same platform as the D-20, with compact refinements in presentation and feature set. The core transport and dimensions remained familiar, but the finish felt a touch more polished and the controls edged upward just enough to separate it from the most stripped-back models in the range. Sony had already proven the format by then, so the line is beginning to widen instead of reinvent itself every year. The D-30 makes the most sense as one of the machines that filled out the middle, where buyers wanted something competent and current without paying for the more ambitious end of the range.
D-600
The D-600 is never meant for pocket carry. Built as an AC-powered unit that could also run from a car battery, it sat somewhere between a home player and a portable, with internals drawn heavily from Sony's full-size CD hardware and a stable signal path that worked well through both headphones and line out. Physically it behaved closer to a compact component than a personal device. Portable CD still had not fully settled into a single use case at this stage. The D-600 could sit on a desk, plug into a home system, or be mounted in a car with the right accessories at a time when factory CD players were still uncommon. It belongs to that awkward but interesting period when mobility often meant "movable" more than truly handheld.
D-2001
The D-2001 is a portable CD player from Sony's 1987 range that added a wired remote to an otherwise straightforward Discman platform. It kept the compact body and familiar transport logic of the lineup at the time, but the remote shifted some of the interaction away from the main unit and made more sense once the player started spending time in a bag or under a jacket instead of in the user's hand. This is the part of the line where portable CD is starting to absorb the compact usability lessons cassette Walkman had already gone through. The D-2001 did not need to reinvent the category. It just pushed the machine a little closer to the way people were actually beginning to carry and use these things.
In 1987, a practical structure suitable for everyday use was established. At the same time, a design structure based on miniaturization was established.
