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OB-4 / Teenage Engineering

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The OB-4, which Teenage Engineering calls a 'magic radio', is a slab-shaped Bluetooth speaker that behaves less like a speaker than an instrument. Available in a range of colours, four drivers and two 38W class-D amplifiers throw a wider stereo field than the size suggests, with a bass reflex duct for low end. The defining feature is hidden: the OB-4 continuously records whatever it plays onto a rolling two-hour loop, so you can rewind the radio, catch something you missed, or loop a passage with the motion-sensing knob. Inputs run from FM and Bluetooth to a 3.5mm line-in and an experimental disk mode. An adjustable handle houses an extra antenna and doubles as a stand, and the battery lasts for days of normal listening. It suits a listener who wants a physical, playful object rather than a smart speaker.

Design intent

The rolling two-hour record loop is the central idea, turning a passive speaker into something you can rewind and replay, with a motion-sensing knob to scrub the recording by hand.
Physical controls, an FM tuner and a handle-mounted antenna deliberately keep the OB-4 a self-contained object, with no voice assistant or app dependency to operate it.

Trade-offs

There is no line-out, so the loops and remixes you create on the device cannot be recorded off it or fed into another system.
The playful interface and unusual feature set place it above conventional Bluetooth speakers on price, where spec-led buyers can find louder or more accurate sound for less.