Bookshelf Speakers — Diapason ÀSTERA

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

Key specs that matter

A 29mm soft-dome tweeter with a Hexadym magnet system works with a 180mm woofer that has a Nextel-impregnated paper cone in a cast metal basket. The crossover point is 1.6kHz, against 4.6kHz in the Adamantes with its 19mm tweeter. Frequency response is 38Hz to 20kHz and nominal impedance is 8 ohms. The 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

The 29mm dome has more radiating area than the usual 25mm and 19mm types, so it can be crossed over much lower and still handle the power. The tweeter therefore covers more of the upper midrange, and the woofer no longer has to reproduce the frequencies where a cone of its size starts to narrow its dispersion. The tweeter motor has double damping, and vent holes in its body keep the voice coil from overheating. Nextel impregnation adds damping to the paper cone, while the cast basket keeps the driver rigid and leaves the area behind the cone open. The cabinets are built from individually cut staves of solid walnut cured for many years, and according to Diapason this wood holds less moisture and behaves better with regard to resonance. Assembled cabinets rest for months before finishing, as a musical instrument would. The faceted front panel reduces edge diffraction and helps the drivers act more like a point source. Diapason crossovers use few parts, polypropylene capacitors and components matched to tight tolerances, and the internal cabling, supplied by Van den Hul, uses silver-plated copper conductors.

Pairing

The benign impedance makes the Àstera an easy load for most amplifiers, valve designs included.

Alternatives

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