Bookshelf Speakers — Diapason ÀSTERA

The Àstera is a compact two-way monitor built by Diapason, the Italian manufacturer based near Brescia in northern Italy, a city with a long history in stringed-instrument making and fine cabinetwork. Diapason was founded by Alessandro Schiavi at the end of the 1980s, and nearly all of its models are two-way designs. First launched in 2009, the Àstera was developed from Diapason's earlier Adamantes and shares its diamond-inspired, multi-faceted front and solid walnut construction, but is larger, heavier and uses a bigger tweeter with a lower crossover point.

Key specs that matter

The Àstera pairs a 29mm soft-dome tweeter with a Hexadym magnet system and a 180mm woofer with a Nextel-impregnated paper cone in a cast metal basket. The crossover is set at 1.6kHz, compared with 4.6kHz in the Adamantes, which uses a 19mm tweeter. Frequency response is 38Hz to 20kHz and nominal impedance is 8 ohms. Bass is reflex-loaded through a port on the rear panel. Each speaker measures 26 x 44.2 x 38cm and weighs 13kg.

Engineering and use context

A 29mm dome has more radiating area than the more common 25mm and 19mm types, so it can be crossed over much lower and still handle the power involved. That hands a larger part of the upper midrange to the tweeter and relieves the woofer of the frequencies where a cone of that size begins to narrow its dispersion. The tweeter's motor has double damping and vent holes in its body so the voice coil does not overheat. The woofer's Nextel impregnation adds damping to the paper cone, and the cast basket keeps the driver rigid and open behind the cone. Diapason's cabinets are built from individually cut staves of solid walnut that is cured for many years, which the company says gives the wood better resonance behaviour because it holds less moisture, and the assembled cabinets are left to rest for months before finishing, much as a musical instrument would be. The faceted front panel reduces edge diffraction and helps the drivers behave more like a point source. Diapason's crossover philosophy uses few components, polypropylene capacitors and components matched to tight tolerances, and the company uses Van den Hul silver-plated copper internal wiring on its speakers.

Pairing

Its benign impedance makes the Àstera an easy load for most amplifiers, including tube designs. Dedicated stands raise the tweeter to ear level, and space behind the cabinet suits the rear-firing port.

Alternatives

Diapason's own Adamantes V is the smaller, lighter sibling with a smaller tweeter and a higher crossover point.