Sony's TC-2850SD "Cassette Densuke" was at the forefront of it all
The "Nama-roku" boom swept Japan in the mid-1970s. As the name suggests, "Nama-roku"---"live" or "on-site" recording---involves making personal recordings for oneself. At the time, most fans focused on tape-based recording of FM broadcasts. However, this was not enough for some audio fans who increasingly felt the desire to to be able to record live sound for themselves.
Sony's TC-2850SD "Cassette Densuke" satisfied this urge. Borrowing part of its name from Sony's "Densuke" professional-level portable tape recorder, "Cassette Densuke" was a genuine high-performance unit that advertising copy described as "A cassette deck that goes anywhere you go." Naturally, it offered such advanced performance that it could also be used as a home audio deck.
The launch of the "Cassette Densuke" triggered a huge craze for on-site recording. Everything became a potential target for recording, from dynamic events like festivals and motor racing, to soothing sounds like forest birdsongs and murmuring streams. It also coincided with the "SL Boom," which encouraged countless fans to collect live recordings of steam locomotives. Tips on the best locations throughout Japan for making recordings were circulated among fans who were drawn by the nostalgia and romance of the steam engine's powerful sound, the piercing note of the steam whistle, and the wish to preserve them before disappearing for good.
Today, devices small enough to fit in the pocket, like Handycams and mobile phones, can record video as well as sound effortlessly, so the younger generation might be forgiven for smiling at the enthusiasm of these "audio only" recording fans. Yet audio by itself has the mysterious ability to bring certain scenes back to life vividly.
The "Nama-roku boom," and the fans who were so enthralled with capturing it realistically, added another page to the history of audio.