WM-EX921

The WM-EX921 is part of the more distinctive late EX-series playback Walkman, notable for replacing conventional button clusters with a multi-function jog-style control interface that acted almost like a miniature joystick. That gave the player a more modern, menu-like handling style than most earlier cassette models, while the rest of the machine retained Sony's mature late-period essentials: auto-reverse playback, Dolby B noise reduction, Extended DBB, AVLS, Automatic Music Sensor, blank skip, a backlit remote, and efficient low-power transport with external battery support. The result was a compact machine that felt less mechanical in operation even though the format underneath remained the same.

This is part of the clearest examples of Sony trying to make cassette behave a little more like newer portable electronics without actually abandoning tape. The EX921 is not important because it changed playback quality, but because it changed the way the user moved through the machine. It is a Walkman trying to stay contemporary through interface instead of through format.