Floorstanding loudspeakers — AudioNec OBi MID

AudioNec, a company based in France, makes three OBi towers with open baffles, and the OBi MID is the middle one of them, placed above the OBi MINI and below the OBi MAX. It is built by hand from high grade materials and combines a full range response with a fairly slim profile, and all three OBi models share the DuoPole 31 driver that first appeared in the brand's Evo loudspeakers, which debuted at High End Munich 2019.

Key specs that matter

The OBi MID splits its range into three bands, handled by separate drivers. The DuoPole 31 wideband driver covers 400 Hz to 10 kHz, a tweeter takes over from 10 kHz to 25 kHz, and two 12-inch woofers handle the band from 25 Hz up to 400 Hz. AudioNec lists a nominal impedance of 4 ohm and a sensitivity of 85 dB. The recommended amplifier power is 150 to 300 watts per channel. Each cabinet measures 35 cm wide, 127 cm tall and 31 cm deep and weighs 28 kg.

Engineering and use context

With this open baffle design no closed box sits behind the drivers. The front and rear waves from each cone are free to interact with the room, and the design removes the resonances that a conventional enclosure adds. The two 12-inch woofers are mounted in a d'Appolito arrangement, with one placed above and one below the midrange and tweeter group, which keeps the radiating centre of the speaker symmetrical on the vertical axis. Because the woofers hand over below the vocal band, the DuoPole 31 carries the entire vocal band and most instrument fundamentals on its own, with no crossover point inside that region. The MID is 28 cm taller than the smallest OBi while keeping the same width and depth, which is where the space for the second bass driver comes from. An open baffle radiates to the back as well as to the front, so the speaker needs some clear distance from the rear wall.

Pairing

With its low sensitivity and impedance, the OBi MID is not an easy match for low power valve amplifiers. The power recommendation points toward solid state integrated or power amplifiers with good current delivery, and in a 20 m2 room the lower end of the maker's range is enough. Speaker cable of generous gauge suits the low impedance, and with the woofers covering the whole bass range the amplifier's grip on the load is the main selection factor.

Alternatives

The AudioNec OBi MINI is the smaller open baffle floorstander in the same range, with a single 12-inch woofer and an easier load.