Floorstanding loudspeakers — Ascendo D7

The D7 is a passive floorstanding loudspeaker from Ascendo of Ansbach, Germany, and within the Coax series it sits under the D9. Stefan Koepf, who heads the firm, based it on a coaxial point-source driver backed by two bass units hidden inside the cabinet. The pair price was around EUR 6,800 in early 2016.

Key specs that matter

Ascendo lists a response of 34 Hz (-3 dB) to 32,000 Hz, a nominal impedance of 6 ohm and a sensitivity of 88 dB at 1 W and 1 m, with a program load capacity of at least 350 W. The front carries a shielded coaxial unit made by Seas, with a 25 mm neodymium fabric-dome tweeter set inside an 18 cm midrange cone of XP material. Two 18 cm internal woofers with NRSC cones, supplied by Scan-Speak, handle the lowest octaves. A single 27 mm magnesium tweeter without ferrofluid faces backwards and can be switched on or off, so the speaker runs as a four-way (rear unit on) or three-way design. The standard D7 measures 23.2 x 106 x 41.5 cm and weighs 38 kg, while the D7-C version is 108 cm tall and 43 kg.

Engineering and use context

Ascendo calls the bass arrangement SASB MKII double-bass technology. The two woofers sit in the lid of a large sealed lower chamber and fire into a second compartment above it, which vents through a wide reflex port on the front baffle, forming a bandpass enclosure. Because a bandpass box has both a lower and an upper limit to its working range, the woofers need very little electrical filtering. The coaxial driver works in its own chamber, and because its tweeter sits within the voice coil of the mid cone, both radiate from one point. In voicing the crossover, the designer matched the in-box resonances of the drivers so that impedance and phase stay close to linear. The rear tweeter, called the TOS unit, is switched by a toggle on the terminal panel. The cabinet has rounded edges, a baffle tilted slightly back and aluminium outriggers with feet. Its piano lacquer is built up from 12 coats applied by hand with polishing between layers, in white or black, and other colours are made on request. An optional C-decoupling base, EUR 1,300 per pair, uses a two-layer steel base in which each foot carries three stainless steel and ceramic decoupling units.

Pairing

The moderate impedance and sensitivity put little strain on typical transistor amplifiers, while the high power rating leaves headroom for strong designs. The terminals take single wiring or, as an option, bi-wiring with two cable runs.

Alternatives

The Ascendo D9 is the larger Coax tower, at 24 x 112.5 x 45 cm with 89 dB sensitivity, carbon fibre woofer cones and two rear tweeters.