Floorstanding loudspeakers — Definitive Technology Dymension DM40

The Dymension DM40 is the slim bipolar tower speaker in the Dymension series from Definitive Technology. The series replaced the company's earlier BP90XX bipole line and consists of four bipolar towers, three centre-channel speakers, a wedge-shaped on-wall model and an Atmos add-on module. Unlike the larger DM60 and DM70, which build in a powered subwoofer, the DM40 is a fully passive two-way speaker. It sells for USD 849 each.

Key specs that matter

Rated response is 55 Hz to 23 kHz at minus 3 dB, and sensitivity is 87 dB. Nominal impedance is 4 ohm, with the maker describing the speaker as compatible with 8 ohm amplifiers, and the recommended power range is 50 to 250 W. Each tower measures 95.1 x 26.2 x 25.6 cm (height, width, depth) and weighs 17.3 kg. The driver complement totals six units - two 1 inch aluminium oxide dome tweeters and four 4.5 inch mid-bass drivers.

Engineering and use context

The bipolar array is fully balanced, meaning the front and rear baffles each carry an identical set made of one tweeter and two mid-bass drivers. The tweeters are hard domes of aluminium oxide on a Teteron cloth suspension, while the mid-bass cones are a composite polymer mounted in long-throw surrounds for greater excursion. Firing sound both forward and backward spreads energy through the space in more directions than a conventional front-only box. A switch on the back panel sets the rear array to a balanced or a forward-focused mode, and in the forward setting the rear tweeter is attenuated by 6 dB, which the company intends for towers placed close to a wall. The rear-ported enclosure is built from MDF and wrapped in black cloth. Spikes and pads are supplied for levelling on carpet or hard floors, and the tower carries a warranty period of five years. The narrow front lets the cabinet fit beside a television or between furniture.

Pairing

As a low-impedance tower of modest sensitivity, the DM40 suits an amplifier or receiver specified for 4 ohm operation, preferably one with generous power in reserve. In a multichannel system the DM40 can be combined with Dymension centre, on-wall and Atmos models, and a separate subwoofer handles the lowest octaves that the passive tower does not reach.

Alternatives

The Dymension DM60 is the mid-size bipolar tower in the same Definitive Technology series.