WM-506

The WM-506 is a wireless playback Walkman that refined Sony's earlier RF headphone concept by adding a built-in microphone linked to the Hot Line function, allowing outside sounds or nearby conversation to be mixed into the transmitted signal without removing the headphones. The player itself retained auto-reverse, Dolby B noise reduction, and Dynamic Bass Boost, while the dedicated wireless receiver-headphones includes their own level of bass adjustment. As with the earlier wireless models, the appeal was not conventional compatibility but a self-contained cord-free listening system.

Sony had already moved past the novelty of "wireless" and started addressing what wireless listening actually changed. Isolation was one of the obvious tradeoffs, and this model tried to soften that problem in a very pre-digital, very Sony way. It is one of those products that is less of a dead-end gimmick than an early sketch of behavior that much later portable audio would revisit more seriously.