Напольная акустика — Opera Loudspeakers Grand Callas

The Grand Callas is a floorstanding three-way design from Opera Loudspeakers, a company based in Dosson di Casier near Treviso in Italy. It belongs to the Callas line and replaces an earlier model that carried the same name. Opera positions the current version close to its larger Tebaldi in capability while asking less money and allowing more freedom in where the cabinets stand. In the US it is listed at USD 14,999 per pair, and walnut or mahogany finishes are ordered specially.

Key specs that matter

Four drivers face forward - two 8 inch long-throw woofers from Scanspeak with aluminium cones and rubber surrounds, a 7 inch mid driver whose cone is annealed polypropylene, and a 1 inch tweeter. Two further 1 inch tweeters fire to the rear. Opera quotes a response of 32 Hz to 25 kHz, a sensitivity of 89 dB at 2.83 V and 1 m, and a nominal impedance of 4 ohm that falls to a minimum of 3.2 ohm. Continuous power handling is 240 W, with 500 W allowed for short peaks. Each cabinet stands 130 cm tall, 31 cm wide and 55 cm deep, and weighs 75 kg.

Engineering and use context

The network hands over at roughly 200 Hz and 2,000 Hz. It is split into two parallel sections built on separate circuit boards, with 12 dB per octave slopes for the woofers and the midrange, 18 dB per octave for the front tweeter and 12 dB per octave for the rear pair. Wiring the rear tweeters in this way creates what Opera calls a natural dipole layout for the top octaves. The midrange cone can move 12 mm peak to peak, which lets it deliver enough output down at its lower crossover point. Internal volume totals 92 litres, of which 80 litres serve the woofers. Walls are made from MDF and curved plywood between 25 and 50 mm thick, braces tie the vertical panels together, and the midrange chamber is packed with pyramid-shaped polyurethane foam. The front baffle is milled to limit air turbulence, and its curved shape allows listening from as close as 1.5 m. The speaker can stand on spikes or on wheels.

Pairing

Opera states that amplifiers from 10 W RMS can drive the Grand Callas, but the low nominal impedance and its minimum favour designs that keep their output stable into low loads. The continuous power rating leaves plenty of headroom for large solid-state amplifiers. Twin terminals allow bi-wiring with separate cable runs for the woofers and for the mid and treble drivers.

Alternatives

The Opera Tebaldi is a larger floorstander from the same maker, a dipole tower with twin 6 inch SEAS magnesium mid-bass drivers, side-firing 8 inch woofers and a 90 dB sensitivity rating.