Напольная акустика — Acapella ATLAS

The Atlas is a floorstanding horn system built by Acapella Audio Arts in Duisburg, a German company founded in 1978 that claims to have introduced the spherical horn that year. It places the large hyperspherical midrange horn, first used on the Poseydon and Apollon, on a lower bass cabinet so that the horn system fits a more compact domestic speaker. US prices have ranged from USD 96,000 to USD 117,500 per pair.

Key specs that matter

The Atlas is a three-way system. Three 10-inch woofers handle the range up to 350 Hz - two firing from the front baffle and one working as a subwoofer inside the cabinet. From 350 Hz to 6 kHz a 2-inch driver loads the 780 mm (30.7-inch) hyperspherical broadband horn, and above 6 kHz the Acapella Ion Tweeter TW 1 with a spherical horn extends output to 40 kHz. Frequency range is given as 25 Hz to 40 kHz in German test data and 20 Hz to 40 kHz in other Acapella listings. Efficiency is 93 dB at 1 W and 1 m and impedance 6 to 8 ohm, with a load rating of 100 W continuous and 1,000 W for 10 ms pulses. The ion tweeter consumes 15 W of mains power. Without the horn the cabinet measures 1,600 mm high, 380 mm wide and 760 mm deep. With the horn mounted the speaker stands 1,890 mm tall, 780 mm wide and 940 mm deep, and it weighs 140 kg.

Engineering and use context

In the ion tweeter a high-voltage plasma discharge moves the air directly, so the top octaves are reproduced without any membrane or moving mass. Handing the whole midrange band to one horn keeps crossover points out of the range where hearing is most sensitive. The large horn diameter is what lets it load the midrange down to its lower crossover point. Internal wiring is ceramic-insulated silver, and buyers choose between black and white acrylic for the body. With the horn fitted, the Atlas is about 410 mm shorter than the room-height Apollon and weighs 180 kg less, so it suits rooms with normal ceilings and floors that would not carry the larger model.

Pairing

The high efficiency and moderate impedance allow a wide choice of amplification, from moderate-power valve amplifiers to large transistor designs within the continuous rating. Acapella also produces its own electronics, including an integrated amplifier and a line stage. Each speaker needs a mains outlet nearby to power the ion tweeter.

Alternatives

The Acapella Apollon is the larger floorstander of the 780 horn series, with six 10-inch bass drivers in a 2.3 m column.