Teenage Engineering has launched a new speaker that looks about as bread-and-butter as they come. It's a matte black box with some useful inputs including Bluetooth, a built-in FM radio and a smattering of buttons and dials. It has two 4in bass drivers, a pair of neodymium tweeters, and a snazzy handle so you can carry it around. Much like the denizens of Cybertron, however, this little gadget is more than meets the eye. You see, the OB-4 (£599) has a hidden superpower. It's actually a 'magic radio' that memorises everything you listen to on a two hour looping tape, allowing users to rewind, time-stretch, and loop radio playback with a flick of their fingertip. It's an ability that has Teenage Engineering referring to the OB-4 an a 'media-instrument,' and the company has pledged to keep adding more experimental features to the device that'll be accessible when in 'disk mode.' Right now, disk mode offers three functions - ambient, karma, and metronome - which, among other things, can be used to generate ambient drone tracks by piecing together snippets of radio broadcasts or record high def stereo tracks at 1 beat per minute, up to 800. If that's what it's capable of at launch, imagine what it'll be able to do in a few months' time.