Teenage Engineering OB–4 black is a portable hi-fi loudspeaker in matte black, designed and built by Swedish manufacturer Teenage Engineering. The design combines two 4-inch long-throw neodymium woofers with ferrofluid-cooled neodymium tweeters, a 2×38 W Class-D amplifier, and an FM tuner with continuous rolling-loop recording — all in a glass fibre reinforced polycarbonate and milled aluminium enclosure.
Motorized interface and continuous capture of everything you play
The volume knob and tape dial are not conventional encoders — they are driven by a brushless DC motor controlled by a Hall effect sensor and an intelligent motor control algorithm. Both elements have digitally managed resistance and motion, allowing the user to literally grab the signal mid-playback and scrub through it with their fingers. OB–4 continuously records everything it plays on a rolling 2-hour loop — Bluetooth streams, FM radio, and line-in sources alike. Real-time FM rewind is a feature absent from any other portable loudspeaker in this size class. Disk mode is a separate space for experimental features distributed through firmware updates: currently available functions include ambient, karma, metronome, noise, and loop.Studio use and connectivity
The 3.5 mm line input with low latency allows OB–4 to connect directly to an instrument, turntable, or audio interface as a portable studio monitor. FM sync enables wireless connection with the OP–1 field via radio signal. Bluetooth Classic handles AAC streaming; Bluetooth 5 LE covers volume control via the orthoplay app and the ortho remote. The folding carry handle houses a built-in spiral antenna for FM reception and doubles as a listening stand. The LiPo battery delivers up to 72 hours in FM mode, 40 hours over Bluetooth, or 8 hours at maximum volume.KEY FEATURES
- Two 4-inch long-throw neodymium woofers
- Two ferrofluid-cooled neodymium tweeters
- 2×38 W ultra-high efficiency Class-D amplifier
- Active crossover at 3.5 kHz, stereo 2+2 configuration
- Flow-optimized bass reflex duct with semi-unified chamber
- Motorized interface: brushless motor, Hall effect sensor, motor control algorithm — volume knob and tape dial
- Continuous 2-hour rolling loop recording — scrub and rewind FM and Bluetooth
- Bluetooth Classic (AAC) + Bluetooth 5 LE
- FM tuner with smart spiral antenna integrated in handle
- 3.5 mm stereo line input (low latency)
- Disk mode: ambient, karma, metronome, noise, loop (firmware-updated features)
- LiPo battery: up to 72 h (FM) / 40 h (BT) / 8 h (max volume)
- Folding handle — dual function: carry handle and listening stand
- Compatible with orthoplay app (iOS/Android) and ortho remote
- Mains power: AC 100–240 V 50/60 Hz (universal built-in power supply)
- Country of manufacture: Czech Republic
TECHNICAL SPECIFICATIONS
- Frequency range: 52 Hz – 25,000 Hz
- Max SPL @ 1 m (stereo, unsupported wideband): 92 dB
- Max SPL bass @ 1 m (supported): 104 dB
- Active crossover frequency: 3.5 kHz
- Configuration: stereo 2+2 (2 woofers + 2 tweeters)
- Amplifier: 2×38 W, Class-D
- Wireless: Bluetooth Classic (AAC) + Bluetooth 5 LE; FM radio
- Input: 3.5 mm stereo jack (line-in)
- Power: AC 100–240 V 50/60 Hz, built-in universal power supply
- Dimensions: 232.5 × 284 × 57.5 mm
- Weight: 1.7 kg
- Materials: amorphous glass fibre reinforced PC, milled aluminium
- Color: matte black
- Included: mains power cable, antenna
